If the liquid could be explosive, why are you dumping it in a crowd?

If the liquid could be explosive, why are you dumping it in a crowd?:
"Mark Frauenfelder: xopl asks a fair question:

So CNN is reporting: 'Because the plot involved taking liquid explosives aboard planes in carry-ons, passengers at all U.S. and British airports, and those boarding U.S.-bound flights at other international airports, are banned from taking any liquids onto planes.'

And then they have the photo of the TSA guy dumping a tub of confiscated possibly explosive liquids into a garbage can in a crowd of people.

Figure that shit out for me."