Well it's early days on running these things and unfortunately, the weather causing water to run everywhere is always a nightmare. I'm sure H&S are pretty much all over this in regards to throughputs. Merlin are prob still in very hot water after allowing the Creaky Cafe (at Chessington) to have an enormous amount of guests in their Christmas walk through, when the building was only ever passed by H&S for a very small number (years before as the original cafe).
At least risk assessment wise, these mazes will have newly assessed, updated H&S regulations, as we saw with the X:/ building restrictions last year, and if you want a vortex tunnel, Hocus Pocus Hall is it!