If you obscure your scan in an airport (say, wrap your stuff in metal foil or put some of those fancy sheets of steel with the 4th amendment cut into it) you get denied access to the plane. OK, that's easy, and it makes cop-sense that you're opting out of your flight if you don't consent to the search. And I guess the same logic could apply to major events and the like, though I can see people having even less patience for the security theater on their way into something fun.
Wonder how they'd take to that just walking down the damn street, though, especially since the chances of blocking the scan on accident are greater in Real Life than in an airport. Knowing the way these assholes think, they might just try to slap you for obstruction of justice or some shit.
I'm starting to think we'd all be better off if there was a virus that specifically targeted cops and security types.