I can see where changing the key of a song might really mess up a drummer.Now for some drama....
We had a new drummer start last Sunday. He practiced with us the week before that and was invited to play last Sunday. He quit via email that afternoon.
It would seem that our tendency to be Spirit-led with regards to changing the set list or the keys of the songs Sunday AM, just prior to service did not fit well into his more ordered life.
I too prefer to rehearse things the way we are going to play them, but understand we do need to be flexible.
and in fairness, TB is probably the best board I've been on for all my hobbies.