How? Do you think the gov't will call a press conference because your car was at 12th and Main? I don't know about you, but I can actually READ your plates from quite a distance. Yup, there they are, as big as day ... legible and readable from 300 feet away. So, how does letting a scanner read that your car filled up at 7-11 on 6th Avenue impact your rights? Anyone who wants to know can SEE you doing this.
From the cost analysis point of view, RF scanners are amazingly inexpensive. The gov't can not do ANYTHING to stop you from driving where you want. You have this freedom; so do the bad guys. Frankly, Trooper Friday doesn't care where you drive; but if you are driving a stolen car, or have a hostage, this will help Trooper Friday chase you down.