MGD - while the hi-viz kit is good, it's not a magic wokka-repelling suit. What if the horse/rider is masked by buildings/trees/hedges/vehicles/the lie of the land?
It's fine if they are riding across a flattish, open piece of ground, but otherwise it's as useful as a chocolate teapot.
If you like I'll ride a pre-agreed route on my grey (white) nag, and you can see how easy I am to spot from your airborne chariot.