I have been giving this thread a lot of thought. While I do not have my DD perform wrist flips during her warm ups, I do see a ton of pitchers who still do. I no longer see a benefit in this drill. I also do not see the harm. When I look at the wrist flip in more detail, it seems like it teaches the pitcher how to throw with their fingers along with snapping the wrist. You can pitch using the "bowling" technique or the "IR" method. In both cases, your fingers snapping through the release are what throws the ball. If a young pitcher can get the feel of the release through a wrist flip, where is the harm? I would certainly make sure the next drill she uses to warm up involves the elbow and whipping action.