A TV progamme (?Brainiacs) tested one of those polycarbonate "glasses" along with many other allegedly unbreakable and protective items, such as kevlar vest, steel toe-cap boots, aeroplane black box, a plastic tray and several other household items.

They kicked them, whacked them individually across a field with a baseball bat several times, fired them out of a cannon and finally placed them in a caravan, which was dynamited. The kevlar vest suffered some little damage, which was reassuring, but the little plastic beer glass survived throughout.

Of course, they didn't do the ultimate tests which were 20 minutes with an unsupervised toddler and 3 goes through the dishwasher.

LTS