Fair enough
I'll update my mental notes as to what constitutes a 'safe' state to save in. I guess everyone in the household idling is the best bet, although may be tedious to orchestrate once per Sim week. My previous play style involved staying with one family until I got tired of them or had some sort of bright idea, and there was therefore a lot less saving and exiting involved.
One final question, if I may? The RTFM implies that the hack will continue to have an effect even after it is removed - does that affect just the appearance of Mr. Humble, or also the existence of the L&P? i.e. in other households that I have played before I put in the hack but not since.