The auto-hide feature of EM allows you to hide while mounted (and presumably to hide other mounted riders), I'm sure this wasn't intended. Couldn't ride it anywhere like that, but from the tests I did I seemed to be significantly more difficult to spot when mounted (well sure, who'd think to look in such an obvious place.. unless you want to believe that we're skilled enough to hang off the side of the horse, like Dylan McDermott in Texas Rangers <g>)

Blend also works, assuming the horse is trained, might want to look into that as well.

~Kyrrian