i am split on this one. sure, the question must get old. but, it is the gate agent's (GA) job to answer the question (in addition to getting the flight out on time). my boss asks me the same question every day but it is my job to answer. i can't blow him off or give him false information (unless i want to get fired).

i think the answer is delta's (DL) monitors. i am sure it must be expensive, but it is quite the value add in terms of pre-departure experience.