I can't comment on the legality of your experiment, I think there are some threads floating around with a list of TSA 'crimes' (try the SAN thread).
Originally Posted by
Bbatchelder
Also, you can only go through the same security check point so many times...could you print up fake boarding passes for different airlines/terminals?
Don't print fake boarding passes.
If I were planning your experiment, here is how I would handle the boarding pass issue:
Buy a (refundable) ticket for last flight of the evening. Go to the airport at 7 am. If anyone asks why you are early, say you hope to go standby on an earlier flight.
You can spend all day going through security, exiting the sterile area, printing a new boarding pass at a kiosk, and repeating the experiment at a different checkpoint. (This will work best if your airport has interconnected terminals like DFW.)
There is no reason you can't print an AA boarding pass and enter the UA checkpoint. If they want try to send you to a different checkpoint, tell them you got to the airport really early

and you want to shop/eat in this terminal for a while.
This would also work on National Opt-Out Day if you want to maximize your chances of opting out.