When a unit wants to perform opportunity fire on a unit which is voluntarily loading on/unloading from a transporting unit, which unit is the target then? The unit which wants to load/unload, the transporting unit or both?
Since OpFire otherwise happens after a unit enters a new hex, and such fire is directed at the unit in the hex it moved to, I conclude likewise that OpFire is triggered by the movement action. Thus Opfire against a loading unit and its transport would be conducted against the transport as in
rule 5.6. Similarly, if the unit being unload is the trigger, the unit is now unloaded and is a separate target from the transport.