A stereotypical stabbing?

Now walking through London the other day I was approached by a couple of tourists who were looking a bit lost as you do. Approaching me the lady said (in an American accent) "Excuse me Sir, do you know where Holborn underground is?" now ignoring the stereotype of the woman asking for directions because the man obviously knew exactly where he was and just had to find his bearings. Got me thinking about stereotypes, it's not very often that I am called Sir and once pointing them in the right direction the classic stereotype line followed "You have a nice day Sir" I thought about this for a while and wondered why I was the one isolated for their question. That's when I realised it was stereotype that may have influenced that as well. It just so happened that I was actually wearing a pin stripe minus the bowler hat and umbrella but almost "the London city man".

Now in the odd way that my mind works and the recent rise in knife crime got me to thinking if I went to America what would happened if I got robbed? Would they approach me say "Sir give me your wallet or I'll stab you" and then follow it up with "have a nice day" as they scarper. Would those Americans be expected to be robbed in a similar stereotypical way in London "Excuse me, may I trouble you for your wallet in exchange for not sticking this awfully sharp knife in you" followed up with "I'm frightfully sorry old chap, but at least the weather is nice". Probably not I suspect both would be pretty similar involving shouting local slang that no tourist would ever be able to understand.