Because we saw very little when I went to one at the weekend.
Firstly, even in the afternoon, it was full of met police mobile cctv vans and police were everywhere.
The rides were shit and very overpriced.
The DC (preschoolers) wanted to go on a little train ride that goes round in circles, so I paid £3 each for them and they got on, then DD started screaming to get off, was trying to climb out and the ride operator had wandered away and was smoking a fag leisurely. He put it out and strolled over to turn it off, by which point she was hanging on the outside. They were the only children on the ride too. He didn't even acknowledge me let alone respond to the bollocking I gave him.
Then I paid £3 each for a 5 minute session in a bouncy dome thing, this time DS was scared and wouldn't even go in. I asked if DD could take his go in the next session and was told no, and the bloke was dragging kids out by one arm when the time was up.
In the meantime I was scared of being showered in vomit from the people on hideously scary rides called 'terminator' etc.
At this point we went to the park and I will never set foot in one again.