Well that's just damn funny(and a little sad), as kids we used the porcelain from a spark plug, of course just about anything hard will bust a window if you can tap the top edge.
Here's a video of the Benchmade Triage hitting a side window from a car. Doesn't have the same effect as the spring loaded gadgets, but who carries those in their pockets all the time any way?
Two of my ESEEs have glass breaker pommels. The 5 works extremely easy. The trick is knowing where to hit the glass. If you strike in the center of the window, the glass is going to flex and probably wont break. There is a lot more surface tension near the edge, which makes it much easier to break.