I want clarification on whether Adventurer Plates could be considered an "Obscene/Indecent Expression", as listed in the Prohibited Activities doc.

If butt shots are a problem, then isn't the glamour the problem? I don't see how it makes sense to strike an account for a butt shot, when if it wasn't for either the glamour or the emote, there wouldn't be any strike. This isn't modded content, this is all available in-game.

What about cases where people have "normal" glamours, but are covering their characters with the Plate Accents, possibly to simulate nudity? How will that be handled?

I believe the best solution is to disable Adventurer Plates by default and to let players do what they want with them.

However, I'm going to bet that SE will just lock the camera movement instead. But players will still use half-nude glamours, so the problem remains.