"Stay in saddle, Ride DC 5: you can react instantly to try to avoid falling when your mount rears or bolts unexpectedly or when you take damage. This usage does not take an action."
This "or when you take damage" is what bothers me. I see nothing at all in the mounted combat section (pg 201-202 CRB) regarding having to make a ride check when you've taken damage. Shouldn't that section specifically iterate this? It seems like a pretty important omission.
I feel like it needs some clarification. Any damage at all? Someone acid splashes a mounted rider for 1 point of damage, and they need that ride check to stay in the saddle?
A charging mounted opponent crits you(while you're mounted) for 70 points of damage, and that prompts the same DC 5/stay in saddle ride check?
Does this also mean that anyone with a minimum total skill bonus check of +4 to ride can essentially never be dismounted until that mount dies or goes unconscious?
I have a hard time wrapping my head around this. Any thoughts?
Might be an artifact from the translation from 3.5 to pathfinder, that was never removed. Anyway, the DC is so small, it should never be relevant for any actual mounted focus character.
As for when you can fall off, theres also when you yourself go unconscious.
When you draw Radience, scream "chaaaaarge", and total exactly -7 on your Ride check, with 0 ranks in Ride...