Completely unrelated, but BA's check-in staff at WAW (contracted) refused to put a priority tag on my bag because it was not terminating at LHR. They claim to have been told that no priority tags are to be used for connecting passengers.

Of course my bag, which was transferred to AA, did not arrive with the other premium bags at JFK. Cost me an extra 7 minutes.

I cannot imagine that is BA policy, but rather some miscommunication with the Polish ground staff.