I believe the DHS, DoD and the TSA ran extensive tests at Aberdeen Proving Grounds on what type of shielding would dampen and contain detonating three 3 oz bottles of common liquid explosives in flight. I believe the one (1) qt baggies was the clear winner. Apparently the explosives in Europe are about 10% less dangerous thus the three 100 ml rule applies over the pond.
MisterNice
ps: this post makes as much sense as most of the other "for your security" fairy tales