Common areas can include car parking and storage cages. Easy pickings for a thief to come in at night with a set of bolt cutters. We had this problem a few years ago, which we put down to a departing tenant keeping a key; we changed the locks and the problem stopped.
I live in a medium size block, and mostly wouldn’t know if someone in the building was a resident or intruder.
Perhaps such an event would be covered by insurance?