Surrely surreptiously recording the incident while repeatedly saying "I do not consent to this search" must provide some leverage when it comes to court.
That's not a lawful reason for suspicion in any of the many states where medical marijuana is legal; I don't recall the ruling offhand, but the court has said this.
There are only two states where there's any question about the legality of recording police officers in public without permission. The laws you're thinking of only require consent to record private conversations, and an interaction with a police officer on a public road is not private.
