This is just me thinking outloud....and maybe it is a stupid question, but here goes.

Couldn't people keep vials of liquids in their pockets or something when they go through security? As long as they have no metalic objects on them, they will not beep and will not be searched. Unless they are being searched anyway, in which case this wouldn't matter.

Also, what about disguising the liquids as, say, insulin which is still allowed onboard? Or get a prescription bottle, and fill it with something else? Aren't these all ways to bypass the current knee-jerk security measures in place?