TSA will punish you for opting out of anything. If you're lucky, the least they will do is hold you up a long time so you have a good chance of missing your flight. I've also had them sexually harass me, and confiscate (e.g. steal) legal items in retaliation for opting out of things I had the legal right to opt out of. They know people are in a hurry and won't do anything about being treated unethically or illegally, because calling them out would require missing your flight.
When I opted out of the scanner once, I had to wait about 20 minutes, and then the TSA agent comes over to do a "pat down" instead, but is going inappropriately slow and squeezing my body, and saying things like "I'd bet you opted out because you like this." I regret not immediately calling them out and filing charges.