I witnessed the pickpocketing several times. Mostly it happens when people leaving the metro car, it gets crowded and you cannot recognize the hand in your pocket. Other places are when you wait in a line, walking busy street or tourist areas. It's okay if you sense your belongings when using the public transportation. I always put my bag in front of me.

"Isyves" is absolutely correct with the observation that Czechs do not hold loud conversations on public transit. In fact, they are usually pretty quiet, in general, with the exception of some loud pub culture ((b)).

I was on the #9 tram in August, and even I was laughing at this teenager who was advertising that he was from Arkansas, by speaking louder than everyone else combined, with a huge twangy accent, and non-stop chatter. Most of the Czechs seemed pretty amused by his conversation, but I think it got old pretty fast, as he did get some mean looks.

I would say that a key factor in blending into that culture is to keep a low profile. I notice that the tourists from "louder" cultures (British are notorious, but Spaniards & Germans are up there, too) get some nasty stares from Czechs. I am sure that any criminals lurking out there just keep their ears open & can target their prey in about 2 seconds!!