The "stand out to blend in" technique has been used a lot in mystery novels.

You don't even need the magnetic sign and a hard hat, just a clipboard, a little frown, and a firm, non-hesitant step.

Cop in uniform on the beat. If you're not a criminal, they're part of the scenery. Unless he's really cute, do you look at his face?

Mail carrier. Blue, white and red, pushing a mail bag. Do you look at his face?

Elderly person or couple walking their dog, or looking for their 'strayed' dog or cat.

Cat trappers (personal experience): trap, stick to hold it open, long string tied to stick. Talk to the people passing -- no one fusses.

Child molesters and many wife-beaters are the most common in real life.

Child molesters simply get a job or volunteer where there are children: teachers, Scouts, Big Brother, Little League, sandlot baseball, etc.

Many serious wife abusers are like two entirely different people. At work, they're the ultimate Mr. NiceGuy, at home they're Mr. Hyde. Well, they're probably psychopaths, too...

Sue