This gets said way, way, way, too much. It is not that easy to pass a steroid test, especially when you are a champion or main event guy and get tested randomly outside of fights. The fact that so many guys with millions of dollars at stake, and the guys with less money overall but a much higher % of their income, basically their entire livelyhood at stake, get caught so often just shows it is not at all easy to do. Tests can just as easily detect screening substances or other evasive techniques; Randleman being an example of a guy trying to use synthetic urine and getting caught. In order to succesfuly cheat a drug test you would need Either a drug that can't be detected yet, like THG (aka the clear), which at one time couldn't be detected; or a masking substance that (A)works and (B) also can't be detected. For 1 to work both for urine and blood testing. Know when you are going to be tested. Fighters get tested randomly now. A completely secure network to get the drugs and masking agents, a connection in a very hard to penetrate organization in the commissions to let you know when you are going to be tested. That means dealing with what amounts to a drug dealer, and a person who is by definition crooked (if he is helping you cheat, he obviously doesn't have very high morals), and of course your inner circle. To have the person who supplies the drugs, the person who helps you cheat, and your circle all both remain loyal to you by keeping your secret, and be good enough not to get caught is nearly impossible for any real period of time. If it were really that easy to pass a drug test, we would not see guys with Millions of dollars or more at stake (all athletes, not just MMA fighters and boxers), not to mention their pride, their career, their title shots. If this were remotely true, it just shows how hard it would be to keep from getting caught, one friend posting on the internet could lead to getting caught very easily. If you are actually telling the truth I would of course be shocked beyond belief.
Drugs are rampant in every sport, some get caught, some don't. But most are desperate to seek any edge they can get when it means money and fame and will easily accept the risk of potentially getting caught along with that. And just for the record, I have no idea if that guy I knew was on anything. I have a history in bodybuilding and competitions and have an eye for that sort of thing, that's all.