Nerf guns, darts or preferly nerf rings would have been better then!I can think of three liquids that a squirt gun could be loaded with to make it into a harmful weapon (atleast good even to scare people on a plane) and give me half a day (with google) I could come up with the formulas for some very mean stuff that probably will kill. Also they would make a great way to squirt gasoline or alcohol on a person, that plus a lighter is a threat in itself.
And remember, the stupidity is not the squirt guns, not that they were playing with them -- it was thier use *INSIDE* an airport. Just like Rob's leaving a bag behind in the plane, in the Post-9/11 world those are things that get you locked up in a little room for 24 hours with bright lights shining into your eyes.
And I don't blame security either if they were grabbed, no matter how harmless your actions were in real life, to them this could be a dry run to test for weaknesses.
Now, if you want real fireworks, have the two Muslims do the same! I am not sure that even the cameras and crew would help then.