I don't know if they have or not, but i'd suspect not. But things like cameras up in the queue lines are needed too. I'm talking of the sections of queue lines that go up round the back of nowhere out of sight such as Nemesis. It used to be a breeding ground for smokers, name writing, etching into the fence posts and general chav goings on.
Personally I don't ever recall seeing any security guards, at least not uniformed (although to be honest I don't think i'd no what in particular I was looking for). :lol:
I think there should be more visual deterences (cameras, guards, signs etc), but trying to not make it look over the top with cameras and people all over would be a difficult balance.
I also think that everything should be delat with by security, from someone being pushed to people looking shady being stopped and questioned. Maybe this already happens and I haven't seen it, so apologies if it already does. :)