it's a bad idea because you play your custom map when selecting the human race which actually is now the Lolz0r race but still called the humans. So I play my game. The next thing I do is play an oridinary melee map. So let's say I want to play orc... But hey, I can't select Orc, I can only select Lolz0r of R0flcopter... Ok, so then I'll select Roflcopter.
When my game starts, I'm ofcourse playing with orc, but it's called the "roflcopter" race...
that's what I think he means