Not amusing - I recall MW mentioning a while back that a group of nubile ladies had robbed him on several consecutive days....
Seriously, though, by and large you're only going to get robbed of a chunk of cash if you're daft enough to carry it in your pocket and let people see it. It sounds as though these ladies were pretty good at their job and probably used your friend's politeness (or maybe interest?
) against him.
Sounds like a good time to learn a few Bulgarian phrases for "I say - do leave me in peace, sweet ladies of the night".