I do know however, just as in any situation with any law enforcement (or quasi law enforcement) that you do not lie to them. You talk around the truth like an Aes Sedai if you must, but don't lie. If you are pulled into a room for more questioning and you're forced to reveal that you lied, it will be much worse to get out of.
Personally, I only do that when it seems like serious business. When I'm pulled over for speeding there's no gain playing mute.
It was more of a "this is what my tax dollars is paying for?" eye rolling moment. That being said, the TSO who joked that we couldn't bring our baby on the plane was apparently loitering not doing whateve her job was and was assigned to go do something by her manager as we finished putting our shoes on, so there are at least some professional in management at the TSA.
I just have to imagine if it was my kid, I would have freaked out and been a little pissed off. I don't think I could have kept my cool as you have, and I fear for the consequences of that.