Oh, don’t get me started. Yes there is a thread from probably 10 years ago. I encountered a pair of endurance riders with a horse running loose while riding a green horse and packing the veteran- and the dam horse came over to sniff noses with my pack horse, getting behind my green horse. I sternly suggested to the two ladies that one of them come and put a lead on their horse post-haste and they said ‘oh, he’ll be okay.’ Honestly it’s a good thing I didn’t have a firearm on me. I hit the beast with my lead rope, they took off at the trot and he then took off to catch them. This was on Forest land.
I do know of folks hereabouts who do it, but truly, it is NOT acceptable unless you are a) on private land and b) have landowner’s permission and c) have the manners and sense enough to put a loose horse on a lead if you see ‘anyone,’ on horse or bike or foot, within a half mile.