This seems a bit unfair?
My friends and their children are at Butlins for a week and asked if I'd like to join them for a day-I had to miss the latest social gathering due to unforeseen circumstances. I've gone to buy a day pass and you need to be at least two of you to buy one. Seems a bit unfair on single or child-free people and I've never been 'told no' when going somewhere alone before.
I've never been to Butlins (or anywhere remotely like it!) however so I suspect I am getting it very wrong and this is a fairly normal thing.