Wasn't there a similar story in Japan? Also multiple stories of people secretly living in office building and warehouses. Gotta make do, I guess.
When workers showed up, they would be 1 or 2 wrappings on the floor and other minor things people would not take major notice of.
He got caught because the night crew schedule was changed and never posted, he was found walking in his night cloths.
He was a in his (low 20s) lived in a forgotten attic above the main store. Seemed he was an ex-employee who had setup a nice small apartment up there. Had a bed, small frig and a TV. He lived there for years.
They never prosecuted him because the company would be embarrassed.
These days I would think that would be very hard to do with all the cameras around.
I know this because I worked at that store right after he got caught when I was very young.
I like to imagine that the visiting professor would come back with some other faculty/staff member in tow saying, "I tell you, he's HERE! sleeping in the lounge!" only to be treated like Big Bird trying to show people Snuffleupagous.
He eventually got an apartment, and I ran into him in that neighborhood so we knew he was really out. I'm not sure what his situation was, we were all quite well paid by local standards.