Well, you're only a out-of-town-peasant so what do you know?
Seriously, they're much stricter searching people at the Amsterdam clubs I've been to than at the London clubs. Here in London security seem more worried about people's safety and all than about someone taking a pill. At a club like Fabric I've seen people snort coke from the table, with security staff around. Impossible in an Amsterdam club like Escape.
Also, it's quite common here in London to go into a cubicle with someone else to do a line (or something else

). In Amsterdam I've been asked to empty my pockets after using the toilet. It's also much easier to find drugs in a club here in London.