I for one would truly like to see UDE give some more rulings for
Autonomous Action Unit as what we currently have is severely lacking.
My assumption of how AAU works is based on other Equip Type interactions we are aware of (
Snatch Steal,
Dark Necrofear, etc.) since
Silent Swordsman LV5 is only immune to the opponent's spells we can surmise that this "borrowed" type of Equip relationship is in play. What the ruling doesn't seem to indicate though is that since
Silent Swordsman LV5 is still considered to be the Original Owner's monster why would it not return to the Owner's side of the field when AAU is destroyed?
We also have no rulings regarding
Imperial Order or
Spell Canceller interaction with AAU. I feel it would be logical that if AAU is treating the equipped monster as "Stolen" from the Original Owner by the Equip it would be fair to say the monster will revert to the control of the Original Owner if AAU is being negated. I would also think that if the stolen monster is flipped face-down with
Book of Moon he would remain under the control of the opposing player.
We've discussed this ad nauseum so I'm sure we aren't coming to a consensus on this but I disagree with your statement. If the monster was brought back with
Monster Reborn and then removed with Dimension Hole it will not revert to the Original Owner when it returns. A
Strike Ninja that was taken from the Original Owner by
Exchange and then summoned by the new Controller can remove itself from play and return to the field without reverting to the control of the Original Owner. The remove from play =
Remove Brainwashing is only present in rulings for the
Snatch Steal type of Equips.
Change of Heart only changes control of the selected monster for a single turn and thus there is never a question of "Ownership", the monster once it returns from out of play will go back to the Owner because it was always the Owner's monster, it was only being "borrowed" for the turn.