I tried this a couple of times, but it never worked. Well, once I uhm ... saw ... an accident involving a random whistler, a stray plated charger and an admin on my team...
Anyway, it would only work when the owner is still alive and/or cares about his horse. As it is now anyone who dismounts his horse expects it to be gone/dead, so most cavalry never dismount even if they could help their teammates better on foot. Almost all stray horses are from cav who died on them or sumpters that are just discarded and only sent running by people whistling or attacking them. So stray horses would still exist for all the things people want to do with them, it would just mean that someone who buys an expensive horse and dismounts it for tactic or fun has less risk to lose it.
