[The_Judge]

At one point awhile back, NWA had a program that anything that was going to be carried on the plane had a carryon tag put on it by the check-in agent. This was to limit the number of carry-ons by a passenger. For example, if they checked their 2 bags and had 3 carry-ons, I would tell him/her that they had too many and had to check one. They would sometimes reply that they'll combine them and/or give one to the person that brought them and have it mailed. If then then showed up at the gate with that carryon-on, untagged, they were asked to check it in.
My point, is if you don't follow the agent's instructions, you still risk an issue at the gate. This is why gate agents should be paid more. They are the LAST line and have to take the brunt of the whole flying experience of the passenger.