I mean that's part of baseball as chess (or poker), right? The batter swaps to the fastball bat, communicating that they expect a fastball. The pitcher knows, from the coach's extensive scouting, and swaps to the curve. But actually, the batter knows he struggles with that kind of fastball and was hoping to bait the curveball, which he's more confident swinging against, and is happy to use a slightly suboptimized bat.