Oh that is expressly called out?
Good point. It doesn't say anywhere the rider benefits from the mounts Disengage action. If the mount uses his action to Disengage it doesn't provoke attacks of opportunity, the rider himself would also have to Disengage if he wanted the same benefit.
Now Dash, obviously since the mounts movement is used in place of the riders there is a benefit there.
Good point. It doesn't say anywhere the rider benefits from the mounts Disengage action. If the mount uses his action to Disengage it doesn't provoke attacks of opportunity, the rider himself would also have to Disengage if he wanted the same benefit.
I say no way. The mount takes the Dodge action. The other two actions benefit the rider by happenstance.I think yes, since the rider also profits from Dash or Disengange, but Dodge seems really strong.
Actually it DOES say that if another creature moves you, you do not provoke opportunity attacks, on page 195 of the PHB. You don't even have to disengage, you simply cannot be OAed if the horse is doing the movement. The disengage action is purely so the horse doesn't get smacked on the way.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.