I do feel adding random noises occasionally could help alleviate some of that. More specifically at the time, a velcro wallet was opened outside a bar and within minutes, at least two people commented in pubSIC on hearing it. As I understand it, those kinds of noises are only made by players currently, so it can be a giveaway to player presence and contribute to smallworlding.
Could even include other random noises than just velcro, such as shouts or gunshots.