Well, I do not use the mod that is entitled "No Mosaic" over at MTS, because that mod says that it is base game only.
If we are loosely referring to any mod that removes the censor blur, such as the one included in AM, then I do use a no mosaic mod. I just use the one included in AM. I have the setting in AM that disables the community lot stalker effect.
I am almost certain that this problem was happening prior to the most recent patch, though I did not observe it happening until after I had patched. But before I had noticed the swarm and before I had patched, I did notice that there was some lag. I have a decently powerful rig, so I guess it didn't pile up enough for the lag to compel me to investigate before, but after I would use resetworld, for a short time, the lag would subside, and after bulldozing the building and the lot, the lag is completely gone. Moral being, that I noticed the lag before I patched, which turned out to be the result of everyone in my hood having 8-12 queud actions to head to the grind. Of course, the cascading pissing of pants and wailing passing out in puddles of piss that followed didn't help...
I don't use HPs camera fix, but jeez, if I wasn't about to move out of a penthouse I would totally get it. I DID use Nraas master controller at the time of the asshattery, though it continued even after I took that mod out. Since I have fixed it I have put the controller back in and no problems have resurfaced.
I'll say though, I haven't been able to figure out how to get a playable lot back onto the plot of land where the grind was, but I haven't really tried very hard to make it happen either (moveobjects maybe?) I dunno, but even if I never get a lot back there I don't care, my game is fixed as far as I'm concerned.

Okay, yeah, so when I said I had deleted the lot before, what I meant was that I had bulldozed the building...the lot was still there, and they were still swarming it. After reading Rushad's post I realized that that wasn't really deleting the lot, and that I further had to delete the actual plot of ground it was on. After using the bulldozer tool on the lot 3 times and completely killing it, the swarming has stopped.
I definately will not miss the grind, Im just glad it didn't happen to another building like Town Hall, as has reportedly happened to some. All I really care is that my townies are acting like townies again, and not being drawn to the Grind like jackals to a fat wounded gazelle, only to get there, see there is no gazelle, then just stand around pissing themselves and passing out. YAY! Thanks Rushad, even though I was just dumb to begin with for not trying to use the bulldozer more than once.
Oh yeah, and I cannot place anything else on that lot at all...it is forever an open plot of land just sticking out into the harbor, but I far prefer that over the asshattery that was going on before...

Ok well here is my experience. The majority of my Bridgeport townies insist upon zergswarming The Grind. I noticed it tonight, only after updating to 1.18/6.1, and downloading/installing the latest AM. I have only been playing in bridgeport for a couple days now, and it is possible this zerging was hapopening before patching/updating AM, but I only noticed it afterward, when the crowd outside grew to about 40 sims. They all just stand around outside, doing nothing except pissing themselves, which causes their hygeine to drop to 0 and begins a cascade of wailing and gnashing of teeth (okay, just wailing) about how everyone stinks. Only about 5% of the total population that arrives at The Grind actually goes in and does anything.
I loaded up a couple of different families and every single one of them had at least one motive (usually energy) at 0/near 0, and every single one of them had 3 queued actions telling them to visit the grind. Even my main sim's father, who is an elderly astronaut widower has 3 queued actions directing him to the grind when I load up his home. Everyone that I load up REALLY wants to visit The Grind.
Shouldnt sims go home when they experience some kind of motive desperation? Isn't that broken if everyone prefers to stand outside pissing themselves?
Just in case it might help - My sim's wife, an up-and-coming actress, once had an assignment to go promote a movie at the Grind by handing out flyers. I noticed when I did that that the challenge completed after I had only handed out 4 of the 6 flyers. I didn't mind it at the time, headed back in to work, and completed my day. Thing is, is a I still have the option to hand out a flyer to everyone who isn't selectable. Since the challenge is no longer active, she can hand out flyers all day long without the option ever going away. I believe this is a bug, since the last time she had gotten an assigment to hand out flyers she completed it, and the interaction went away. I wonder if this zergswarming at the Grind may have something to do with the fact that they were trying to populate the lot so I could hand them a flyer, but perhaps a glitch ended the challenge prematurely, but failed to end their zergswarming? I dunno, just a thought.
So, I saved the lot to file, deleted it from the hood, figuring, "they won't zergswarm an empty lot", but I was wrong. When I deleted it AM (I think it was AM) even told me that the lot had been set to "No visitors Allowed", but apparently the sims didn't read the sign cuz they still zergswarm the empty lot.
ResetSim and Resetworld make them go away, but they just come right back to the empty lot formerly known as the Grind. Actually, resetworld is quite comical, because afterwards neighborhood view kinda turns into Dawn of the Dead, with the lone living breathing survivor seemingly lying prostrate and bound at the Grind.
Um, in case it turns out to matter, I have the option enabled in AM that stops the town from closing in on you like the Mossad when you visit a community lot, which, I do believe is working, because they certainly aren't flocking to the grind because I'm there, cuz I have not been there in about 2 sim weeks.
Lastly, I saw in an earlier post that this may be the result of a lack of computer awesomeness, but I would think that with 2.93 Ghz processor, 8mb of RAM, an nvidia gforce 9800gt and upgraded power supply I would be able to outpower any problem Sims 3 is likely to have in that department.

Edit: So I loaded up the other families now since I have deleted the grind, to check their action queues, and they are all still 30 seconds from passing out when loaded up, and now instead of 3 queued actions to go to the grind they have like 12 "go to Lot" actions queued, which seems interesting, because you can only assign them like 7-8 actions normally. After a couple hours playing around with this I have realized that as is, my game is pretty much unplayable. I mean, my family is fine, they are doing everything normally, its just that I can't do anything involving other sims. My law enforcement sim cant do any reports, because I cant work people into a friendly mood because the interaction string keeps getting interupted by them passing out, pissing themselves, or having some motive desperation, screaming about an adjacent smelly sim, or them trying to move to a new spot within the lot. My celebrity wife was able to attain 5 stars, but it is useless now because no one goes to any bars (they are all on the grind lot), and people still have parties but I go to them and no one is there. Even the host/hostess of a party will drop queue and sprint to the grind before the party even starts. This is to say nothing of the fact that the entire town is a ghost town, and only consists of people heading to the grind, or going home because they are about to die. And immersion is a thing of the past. Every celebrity just stands there like a zombie smelling and pissing themselves and passing out all day long. Some people still go to work, but most dont. They just hang out on the empty lot. If I let it the crowd will grow to over 50, and get to the point that each sim's model is loading one by one cuz there are too many sims on the lot. I tried turning the empty lot into a residential lot - still they come in droves. I get 10-15 townies passed out at a time, all in afore-made piss puddles. Ah well, back to Fallout for now. I know this will be fixed at some point, whether it is a problem with EA (most likely) or AM, it'll eventually be fixed.