Originally Posted by lincolnjkc

The concept (which I think is somewhat flawed but makes sense at certain levels) is "voluntary separation".

You aren't allowed to do something that voluntarily separates you from your bag-- e.g. choose an earlier/later flight after bags are checked for "no reason" the fear being that if you had something "bad" in your bag you could "harm" the aircraft if you knew it was on a flight other than the one you're on.

On the other hand changes that are other than voluntary separation (operational need, irops, bag just happened to get there early/late whatever) are allowed, at lest for US domestic, since you don't "know" that your bag is on a different flight/aircraft.

pmUA agents seem to be generally more strict about preventing voluntary separation under any circumstances OTOH, pmCO agents will bend a little bit more if there's something in it for them (e.g. resolving a potential oversell later in the day, avoiding impending but not yet irops-causing weather). I think some of that may be training, I had a pmUA agent insisting that it wasn't possible to check a bag as a revenue standby until I walked her through it (and she commented that she had never seen the the RVSB VIP notation on the bag tag when it printed)