fparker --

I think the FA should use all available means at her disposal to stick to keep people within the official carry-on policy. However, that does not include lying.

If the passenger put up a serious protest, she could have simply said, "Sir, federal law requires you to comply with my directions, and I'm directing you to gate check one of you bags." That would have been 100% true, and would have been effective. Most importantly, it would not have meant lying to the people who pay her salary.