I think we should be looking at the difference between recreational and performance enhancing drugs. I think just about everyone agrees that marijuanha isn't going to make anyone a better player, quite the opposite if anything, so we probably shouldn't worry about testing for it. However, there are other drugs out there that can make a big difference to sporting performance - if the didn't make a difference then why would athletes take them?
We also have to look at what types of these drugs would affect the performance of someone competing in PAINTBALL events. The recent case of a British skier being stripped of his medal illustrates this - the drug he took in error would actually be more likely to have a detrimental affect on his performance in that particular event, but as it was on the IOC banned list then he was banned. In Snooker beta blockers are banned as they can effect how steady the player's hand is, but no-one who competes in a physically active sport would consider taking them.
Sadly as the sport gets more and more mainstream & hits the big time, I think we will eventually find some forms of performance enhancement drugs being taken by the biggest teams of the future just like the cyclists of the Tour de France or the athletes of the old Soviet Block.
On a lighter note - as someone earlier in this thread said, if we banned the most popular recreational drugs we'd end up with tournaments with about 2 people competing!
