Falconfool, you are right that "instant-on" poses additional problems. The really dangerous traffic cop(to us) is the guy who keeps his unit turned off until he has you at close range, then zaps you. Or is parked where most of his signals are blocked by turns,hills, bridge abutments, etc.
Fortunately, most cops catch all of the speeders they need just by driving around with their units on. Front or rear,with the Valentine I usually pick them up miles away, and by watching signal strength often don't even bother slowing down for a while.Also, most instant-on jockeys when parked can't resist zapping a lot of cars. I have picked up the scatter from cars getting zapped ahead of me, even though the cop was shielded by a turn. I have also picked up scatter at a distance over hills. It all helps. As Falconfool says, you aren't suddenly immune to radar or laser.Still,common sense, combined with constant use of the Mark 1 Eyeball and a Valentine will save you most of the time.