No horse policy exists yet and none can be made yet. For example leads have absolutely no support right now, there is no way to detect when a lead is being removed from a fence. Same with donkey chests & probably more stuff I just don't know of yet.
I think there was a bug which caused horses to disappear as if they are hostile mobs, this should no longer happen.

Refunded you money for 1.5 stacks of nametags