Last night my friend was stopped and checked at EVERY point before boarding. In the jetway while waiting to board, I said "You must have that terrorist look". Everyone around me was shocked I used the T word. FOR GOD SAKES, listen to how I used it. I didn't say that he WAS a terrorist.
While I think there should be no tolerance of joking around like "I have a gun" or "I am a terrorist, I do think that we cannot simply make certain words forbidden.
Your daughter's comment was on the boarderline though. I still think that she was fine in saying it.