Because I know some of the Balance testers. They kicked my butt repeatedly in the past...I wont ever forget that 
They should! The majority of them that I've audited are top 100 players and in some circumstances top 10. Which brings up an interesting point. Go back to when the thread about 'lets be awesome together' was made. Remember that whole debate about Relic not supporting the hard core players? Well, there are certainly a lot of hard cores on the beta team. I'm looking forward to completing my review of the composition of the beta team. I've received a PM from one and he didn't yell at me. That is pretty cool.