The reality is offeason testing is incredibly rare in general and people always seem to have an uncanny ability to be hopping on a plane to another country right before WADA shows up at their home.

Neil Armstrong dealt with drugs with different half lives than AAS, but he still could have been tested at times where they would still be in his system... yet how long did he get away with it? While being tested far far far more frequently than, say, an MLB player.

You'll notice more a decent chunk of the MLB players that get popped get popped for PCT drugs at the end of the offseason - ran their cycle too long, decided to PCT instead of just go cold turkey, and next thing you know, Profar is getting popped for hcg and Severino for enclo.