CCW laws vary a great deal from state to state and judging from posts I've read on here you would be in violation in some states if your gun printed. Here in Michigan that's not a concern, but I still prefer not to have my gun print when I'm carrying concealed.
First of all, don't ever underestimate what may provoke a "concerned citizen" into calling the police!
Secondly, you just never know how street savvy the person(s) is/are that represents a possible encounter. If he makes his living on the street he will know exactly what that bulge is and he will probably either choose to pass you up for an easier score or just go ahead and take you out if he thinks you're not alert.
Myself, I'd rather not have anyone know I'm carrying, leaving me the option of when, or if, to make it known I'm armed.