Ok - Whacky idea but what if the decision as to "advantage" or no "advantage" was determined by a shooter's peers? Something like an odd number of other AAs (As, etc) picked at random and asked to make an opinion on an AA exemption? Which is basically what people are doing now after the event and looking at the video clip :-(
The onus shouldn't be on the Chief Marshall for all the above reasons, can't really just be left to the shooter claiming the position change so it has somehow to be fellow competitors in some way or a judging panel, etc.
Tricky ... needs resolving though as only ill-will can come of the current rules interpretation