Whoever is making local decisions in the LGA station probably directed CS agents to use the 4-hour "rule" regarding Rule 240 to OAL--for whatever reasons that stand to benefit them locally but not necessarily the customer. Seasoned travelers know it's pure bull and can smell it from across the East River.
Personally, I'd roll my eyes, excuse myself, and call UA without putting the phone agent on the spot about what the CS agent had said. That's how this game is played--before, now, and as far into the future as I can tell. There's no need to embarrass any additional person, as long as you got the desired outcome. Besides, because I had been on the receiving end of such convos, I have some sympathy for them.
