It is VERY tempting to put this to the test, and to ask a few stewards, trainers and BHA security staff whether, for instance, I can back against my horse, whether my partner can lay my horse, whether I can lay a horse in my stable, back against a horse in my stable (of which I have been occasionally "guilty", through inattention more than malice) or whatever. I would be astonished if I got correct answers from everyone.
Instead, I have written to the ROA asking whether they feel any imperative to assist new owners on this matter.
Incidentally, while I joined the ROA voluntarily, I do not like the cut of their jib in many respects. Refusal to join the ROA should not make you a second-rate owner or cut you off from advice that is needed by you as an owner.