You don't have to fear getting mugged in the streets, but you can still get ripped off.

One example are the notoriously expensive bars in Roppongi, at night there will be touts in the streets trying to convince tourists to join them for a night of drinking. They'll then go to the bar that hired those touts where, after a night of drinking, the tourists will be presented with a bill that's the equivalent of getting robbed.