A year or so ago a local high school team went to europe to play several games, and encountered the penalty-shot playoff, much to their dismay. The explanation that they recieved was that ice time is at such a premium on most european rinks that the only alternatives are a very fast tie-breaker, or letting the ties stand. From what I heard, many of the rinks are busy 24 hours per day, and it is not uncommon to only resurface the ice between games. It is not clear to me that this rule should be followed when there is no time pressure, though. Overtimes are MUCH more fun!