I make a point of trying this machine whenever I go to the MGM Grand. I hit three red 7s on it for a nice $300 win once (and I took the money and ran!).
You will be protected by gaffed machines by wearing a tin foil hat while you play the machine. I recommend wearing the tin foil hat while playing any machine just to be safe.
The MGM could probably give away the progressive money in a drawing like the Sahara did when they closed if they were so eager to get it off the casino floor. My guess is that they have already made a lot more then 2 million from that machine and keep it in play because it is a good draw to get customers in the doors just like their Sigma Derby machine.