I can't see a un-marked bike or car as entrapment. Entrapment, to my understanding, is doing something to cause you to break the law.
The issue I have is in this day and age, where everybody is certain criminals are everywhere and out to get them, and anybody can buy run flashing lights, do you stop for a un-marked car/bike?
Last time I got stopped in my home town the first thing the officer heard as he approached my window was my "hands free" phone say "911, What is your Emergency?" "THERE IS A MAN WITH A GUN COMING TO MY CAR" There was a audio recording of the encounter that neither of us could edit.