This is kind of in my wheelhouse so I’ll take a crack at it. Poster #2 is correct in that the bag’s sort status is related to the pax record, not any accoutrements on the physical tag. A priority bag will get a reject message on the handheld scanners used by the sort room staff if an attempt is made to scan it into a non-priority container and vice-versa no matter how many fancy flags are on the tag.

The end result is that any given containerized flight should have pure containers for priority bags, regular bags, connecting bags, etc.

The $64,000 question is whether these policies are adhered to, and that varies widely. For a priority container to get the true priority treatment, it has to be assembled, loaded, unloaded and dispensed in accordance with policy. If any handling crew fails to follow policy, you’ve going to have a product failure.

For example, at a major hub like YYZ, the offloading ramp function and the dispense function are handled by separate work groups where the former hands off to the latter. If the offload crew has two strings of arriving baggage containers (a single ramp vehicle can pull a maximum of six container dollies and a heavy widebody flight can easily carry 20 baggage containers) and for any reason the priority container is in the trailing string, the dispense crew is not going to hold off delivering string 1 to wait on string 2. There’s just not enough slack in the work schedule to rearrange the strings. Thus, that priority container will not be dispensed first, despite being assembled and loaded in accordance with policy.

For non-containerized flights, all bets are off. Those flights are loaded by hand and the priority bags are supposed to loaded last so they are in the cargo hold doorway and first off. I’ll be the first person to admit if a crew is loading a flight and a priority bag comes up the conveyor to the belly in the midst of a load, it’s very difficult to put that bag aside somewhere to preserve its status and it’s also very difficult to stop or reverse the load process without sacrificing precious time.

Like I said, if at any point in the handling chain the bag fails to be sorted correctly, the whole priority handling process breaks down and is hard to recover.