Auto dismounts when the error messages "You are mounted." triggers.
This can be very helpful for quests and other things where you would normally have to dismount manually.
It has a check to not dismount you if you are flying or targeted by one of this ground effects:
Fleet Winds (Jade Forest),
Gross! (Valley of the Four Winds),
Consuming Rune (Krasarang Wilds),
Overcome by Anger (Kun'Lai),
Wild Energy (Isle of Thunder)!