What would happen if you get pulled over but cant provide proof of registration?

According to the "Letter of the Law", you would be subject to arrest. However, in real life, typically, if you (and the officer) are BOTH in a good mood, you will get a ticket for not having your registration in the vehicle. They can run your plates via radio/computer, so they will verify that your registration is current, and (most likely) NOT impound your car. But it IS like a fix-it ticket, you go get the registration form, take it in, and get the ticket signed off...