That's the problem is that there is no set guideline to what they determine to be excessive. After reading the forum on Best Buys site I saw quite a few Silver members like myself that got cut off for not that many returns/price matches. If they said a certain amount cannot be returned over X period then at least we would know but they don't do that. They just cut you off when they feel like it. At least they give you a warning though and don't reject your return but still I spend too much money there to be accused of excessive returning. I'd rather just take my business elsewhere. If I wasn't a Silver member it wouldn't be as bad but knowing that I spend a lot of money there it makes it unbelievable that they treat loyal customers like that.
My local BB said it's 3 returns in 30 days. I have no idea if that's actually true, but there you go.