Out of hundreds of shops over five years with MF, I've had three strikes with them, one time violation, and twice wrong locations, but only once have they not let me re-do a shop (they paid me a bonus later that month to do that one, though.) There is a great interview with their CEO in the latest Mystery Shopper Magazine where the author tried to get an answer from him regarding deactivation.
My advice, aggiejim72, would be to not worry about it, but also to prepare for it.
Diversify.
40% of your income with one company is a lot. When CORI went through their computer troubles in the winter of early '03, I had 50% of my income with them, and was nearly wiped out in one month. Thanks to finding the Forum, I was able to diversify from shopping for 7 companies to now shopping for over 50, I'm not overly dependent on any one of them, and my MS income has tripled.