I’m pretty sure you can already get to that little beach just on your horse without glitching. There’s no way up onto the cliffs to get you into Mexico from there unfortunately. Still this is a cool glitch that may have it’s uses.
Doing this same glitch using the bullrush at the edge of a tall drop will also allow you to safely travel straight down unharmed. This can be used to quickly travel down cliffs if you don’t feel like finding a way around. I’ve done it off of massive cliffs and bridges, and into the “bottomless...