Absolutely has happened to me. Not just once, twice, but 3 freaking times!
The first was at East Spa in macau, to see my boss coming out of the shower with a smile on his face then he seeing me
The next was in TST going to a walk up and I meet my high school buddy coming out, while tucking in his shirt, slightly flushed
Last was in Bkk when I inadvertently bumped into my brother in law while out clubbing with a lovely lady (he had one too though!)
So yes it is possible to bumb into people you know....no matter how devious you are