Your first suggestion of a resumé guests would make is one that can only be made about crowded parks, but not badly operated parks. I've been to Efetling's long summer nights plenty of times, and yeah, all rides have 30-45 minute waits on these days. But it's fine, because the park is operated very well, in a sense of lines moving decently quick. Compare that to Alton Towers, which has one third of Efteling's attendance, twice as many coasters, is just as expansive in terms of area and has barely open at all (most of the time 7 hours tops). And I see long-ass queues everywhere. The GP might be not, well... let's say "educated" in terms of the amusement industry, but they cleary know when they are being shatted.