Travel Scams - be alert

Unfortunately one can look very much like a tourist when travelling and attract the unwanted attention of those wishing to liberate your cash from your wallet.  Smartertravel.com has several good travel tips written by the semi famous Rick Steves.

No matter what country you're in, assume beggars are pickpockets and any scuffle is simply a distraction by a team of thieves. If you stop for any commotion or show, put your hands in your pockets before someone else does (or, even better, wear a money belt).
Just because someone looks official doesn't mean they are. In Italy, "Tourist Police" may stop you on the street, flash their bogus badges, and ask to check your wallet for counterfeit bills or "drug money." You won't even notice some bills are missing until after they leave. Never open your door to "hotel inspectors." One waits outside while the other comes in to take a look around. While you're distracted, the first thief slips in and snags valuables off your dresser. In Vienna, official-looking women decked out in long velvet capes roam famous sights, claiming to work for the opera house and offering to sell you tickets. The tickets are fakes, and the only seats you'll be buying are the ones on the bus back to your hotel.

While I quote some passages I'd suggest you read the whole thing.