Originally Posted by
Often1
It's possible that the UC agent ought to have known better, but it's not part of her job to deal with TSA's errors.
I expect UC agents to know what all codes on a boarding pass mean and not assume that all passengers do. If an airline wants to avoid this sort of situation a boarding pass should include something along the lines of "SSSS - this code means you need
enhanced TSA screening before you can board this flight".