I always check my mirror when I'm slowing down or about to make a right turn, to make sure someone isn't going to plow right over me. If you have the concave mirrors that show you more area, they can be very useful. Full-face = hard to see behind you.
That's really shitty about your bike. You could complain about the cop, obviously _he_ didn't steal it, but you can still say "I had a mirror on it, but he still made me leave it with a shitty lock on it, now it's stolen AND I have to pay the ticket." Writing a letter won't fix your problem, but you should always do it when you can. There's a reason politicians and shit listen to old people, they have nothing better to do than write letters and complain, etc.
Ain't nothing you can do about this. You were doing the 'right' thing by obeying his orders, but then again, you probably should have walked around the corner, had a smoke, then gone back and rode your bike home.
I'll keep my eyes peeled.