As an example of what can happen I had an LHR-ORD flight in the Air Belgium period. I decided to go to the B lounge as the odds were good and the flight did eventually pop up on the screens as a B departure. Then it disappeared so I asked at the service desk and learned that this was a sign that it was probably now using an A gate. The agent checked and it now showed A10 however, since the timing was now tight, she checked with operations who confirmed it. There was still time for a comfortable walk back to A so all was well. We had a long and tortuous ride to what looked like a maintenance area to board. So my conclusion was that they were fixing something and hoped to have time to tow the aircraft to a gate. It did not become apparent until a bit late that they wouldn't make it and so it was switched to the bus gate. I don't know whether lounge agents should be calling operations but it was certainly comforting.

Edit: for completeness I should add that the agent then announced the gate for the benefit of anyone else in the B lounge.