Let me clarify, I use the word 'airport' very broadly to include the physical plant, equipment, direct employees, and contractors. In the case of IAD, I presume that each *A airline contracts either with UA directly or the UA baggage contractor for baggage services as there is (almost) always a UA representative at the international baggage carousel for the *A airlines.

This is a people problem; has nothing to do with infrastructure. Best case, it is a lack of training. Worst case, the handlers don't care. (And, by the way, domestic IAD UA flights have good priority baggage handling.)

This brings me back to whether or not *A monitors such things. Priority baggage handling is a published benefit for many situations for customers of *A airlines. If the 'airport' is not complying, the entity should know. I did report this to TK via its feedback form.