Ryanair's rep virtually stomped his feet in the media equivalent of a temper tantrum over us. "Passengers are made clearly aware of their cabin allowance at the time of their booking and it is also printed on their online boarding cards," he said. That means that if passengers refuse to pay up, they can't fly, because they agreed to the baggage terms when they bought their ticket.
Think it couldn't happen here? It can and it will. The American airlines have been moving toward Ryanair's model of charging passengers for every muscle twitch, and with baggage allowances dwindling and per-bag charges escalating, our own carriers know that there's a cash cow waiting to be milked at the departure gate. They have been prepping us for this step for many months now.
All carriers need to do is assign a single agent to enforce the carry-on rules when you hand over your boarding pass for inspection. Give that agent a hand-held, wireless credit card reader, and the revenue stream will become a flow.
Ryanair always charges for checked bags, and that fee starts at €15, or about $20, for one seriously underweight bag. The gate-check fee for extra carry-ons is twice that. Should American carriers adopt the same zero-tolerance policy and charge double for the sinners they nab at the gate, the usual $15 per-bag fee would become a $30 per-bag fee for everything you tried to sneak by the Gate Gestapo.