I've several related issues:
(1)I was attending a conference in Wash. DC in 1975, I checked into a cheap motel on NY Ave. what I didn't know was that nearly all "guests" were permanent residents and/or hookers; their record keeping was not too good, at 2 am someone tried to gain access to my room using a passkey [I had chain on door], about 10 minutes later my phone rang: "did someone just try to get into your room...it was 'us' [management] are you supposed to be occupying that room?", me: "yes, I checked in earlier..."
(2)In Atlantic City Casinos several years ago on a few occasions I was given a key to an occupied room, once I was the third person that was given a key to a particular room.