I agree with Dave. I had a B&M before I started racing, and I would dearly love to have it back in my car, as I think the 1-2 shift would improve my times a bit.
That is not to say that I would protest a shifter if I saw one, though. I am rather passive about that kind of thing. If you wanna race with a cheat, then go ahead, but it is not my style. I will likely notice, though...Maybe point it out as well, but I won't cry to the officials about it : )