I've been aware of an "enforcer". One (late) shihan would send one of his higher ranking students/uchideshi to dojo where either a sensei or a higher up student wasn't doing things "right". AIUI the "enforcer" would spend a little time "practicing with" the person who was being a problem. There may also have been some discussion, but (and this is all hear-say) the problems would usually resolve.
I'm not sure that I would call that "Aikido martial law protocol", it seems like a normal part of group dynamics.
FWIW, I really dislike that kind of passive-agressive response - although it seems to be quite common in Aikido. If the shihan has a problem with someone than they ought to stand up and talk to them directly, not take it out on them on the mat or (even worse) send someone else to do it for them.