Sorry to hear that. We are very careful about this and we hate to get a beer that won´t go up to the fill line. The Czech drinkers are perfectly familiar with how these things work and thus cannot be ripped off but some pubs may still try to serve these "overly foamy" beers to foreigners, unfortunately... But like I said, we always need to have the "cap" (as well call it) on the beer :)
Ah yes man, that was probably it actually, we were young and clearly tourists! I like some foam on top of a beer for sure, hit not too much! 😃