Potentially silly question

I didn't used to think this would cause corruption. However, I was looking for a mod one time where I read that Mootilda's neighborhood, lot cleaner or something was based on the assumption vacated lots didn't hold any data but someone later found they actually did. This was over in a long conversation on MTS from after she passed. It is possible they hold data from visitors to those lots (walkbys and others) who stopped by the lot or visited. I don't know about this but it was later decided previous occupied lots actually do hold over left over data. But in many cases you would not notice any corruption for many Sim years later in your neighborhoods. The Riverside neighborhood (custom) is an example of this, where there is left over data on Sims and in lots where the creator removed Sims (maybe even deleted some) and the data remained on the actual lots. Another example is if you have ever downloaded a lot you assumed was never used and lo and behold there is a Sim (perhaps a Sim who visited and or walkedby) and their information was not seen in the Sims2PK cleaner when you installed it. ETA: This stuff happens during saves (invisible stuck Sims on a played lot) depending on when a player saves their game, like when a Sim is on the phone or a walkby is out front etc. Those files can be attached to the lot even after vacated. But we won't see it unless perhaps we download it etc and actually see the Sim. But in most cases we never see the Sim but their data remains.