Something has confused me about boarding passes:
It seems that the Pre-Check checkmark on your boarding pass is what lets TSA officers know that you should be allowed to go in the Pre-Check lane.
Simple enough. Now, pretend you're a "bad guy".
Isn't it trivial for you to just print a fake boarding pass with the checkmark?
When you get your actual boarding pass, you can of course use it everywhere except at the security lane. For the security lane, you just use the fake one so they think you're Pre-Checked.
Do they even try to guard against this? If so, how? I haven't managed to figure it out.
If not... has it not occurred to them? Wouldn't this completely nullify any security benefit of Pre-Check?
(Note: while I realize that if they decide to check you anyway, then you'll be screwed, that's always a risk even if you really do have Pre-Check.)