Your entire scenario rests on the fact that you are expecting a negative interaction with the police. It's one thing to go into a protest knowing confrontation is likely, it's quite another to have expect that same confrontation during a normal traffic stop.
If it's important enough to video, I'd say it's important enough to backup given how ubiquitous and cheap doing so is these days.
I get your point, but given the current environment with respect to video and journalists it does seem a bit naive to NOT have some expectation on any interaction with authority these days. It does make me sad to have to think this cynically.
Your entire scenario rests on the fact that you are expecting a negative interaction with the police. It's one thing to go into a protest knowing confrontation is likely, it's quite another to have expect that same confrontation during a normal traffic stop.