My question involves a traffic citation from the state of: Pennsylvania
My registration expired 3/31/10. On 4/1/10 I renewed my registration online with the PA Dept. of Transportation. I have a printout that can be shown in case of being stopped by the police. I have not yet received my new registration and sticker.
I parked my car on a half street and saw that I had received a ticket for "Parked with Expired or Missing Registration", "Registration Sticker Expired".

I am wondering, do the police drive through half streets looking for cars with an expired registration sticker? I was legally parked, and all paperwork is legal, just have not received the sticker.

By the way, I have been driving locally with the expired sticker from 4/1/10 until 4/9/10, and have not even been stopped. This seems a bit suspicious to receive a ticket on 4/10/10 while my car is parked on a small street.

I do suspect someone reporting me, but most importantly, can I fight this ticket? ($50)

Thanks in advance.