I've been scouring the internet for an answer to this and can't seem to find an answer. If you are mounted and move out of a threatened square, does the enemy get an AoO on you or your mount? Does it get to choose? If it has combat reflexes can it divide them up however they want?
Both. You're both moving out of a threatened square, so you both provoke. The enemy can choose which to execute, just like with any other provocations.
