Packaged Lot Files. Are any of them safe?

[LadyCrimsonSkye]

While doing some research yesterday, I ran across a site (SimsWiki) saying that ANY previously occupied lot, whether empty or not while packaging, was unsafe to package for installation later.  Is this true?  Could I get some clarification/explanation, please?

[J. M. Pescado]

Assuming a lot is cleansed of all inhabitation and inhabitant-related relics like tombstones, it SHOULD be relatively clean, or at least no worse than any other lot...but it never hurts to sweep it with that CleanInstaller thing.