The Bills seem to do this frequently (moving up a handful of slots) and I'm not a fan of the tactic.
I don't mean moving up from 21 to 7 to get your QB of the future.....that's different. It's locking into one guy in the 2d/3d round and giving up valuable assets when a guy might have been there anyway, but if not it's hardly a franchise changing event, and there are plenty of other needs/guys you could draft anyway.
Maybe it hasn't been that often, but you think about Ragland, Graham, Jones and those were wastes of extra picks.