if the cops come to handle a trespassing call, and the unit is filled with their furniture, they will assume they have established residency and they wont arrest. if the cops show up and there is a broken window and an empty apartment, you have a much stronger case for trespassing.

You could come at this kind of sideways.Find places that have the services and busineses that "income challenged" (RENTERS) like to use.Best would be if within walking distance, things like rent to own furniture, liquor stores, convenience stores, fast food - McD's Jack in the Box, 24 hour car parts, health clinics, (Bus Stops), buy here pay here car sales, a grocery store, Target, WalMart, auto repair shops, etc..Things they need and can afford.  

@Rudy Manna..It depends on how much trash/furniture.  

As one of the units I bought came with furniture I am seriously considering a go at temporary rentals like the AIR B&B model. 

I'll get a call for a LL credit reference from a financer of furniture or cars and think 'that renter ain't goin' nowhere'.

If you have furniture in the house, then cover EVERYTHING.

So you will want nice looking furniture (not necessarily high quality, just nice looking).

There's pre-designed doors, windows, furniture etc that you can drag-and-drop. 

Restocking and furniture upkeep - $2500/year.

I remember that the rental offers topline furniture, cleaning service, and pots/pans, even glassware.I do not know what is the difference in rental pricing though.Update on ADU: just got an email from the city reviewer, saying that my email has been forwarded to the deputy fire marshall of San Mateo city for review.