WGs may have someone else in their flat, whether that be a Boyfriend, female friend/fellow WG as a safety net, some might not... Some may text a "friend" before a booking starts/ends to say they are ok, or feel safe...
One thing I do believe might freak a WG out is when a punter turns up for a booking and asks if there is anyone else in the flat, or even asks in comms (can come across as creepy) ... As much as I understand that can work both ways (nervous punter etc) I think some punters may have to assume there may well be someone else there in the background, as a poster earlier in the thread has alluded to...