Andrea Sachs at the Washington Post travel blog is seeing red over the airlines quest for green - at the expense of travelers who follow the rules:
During my travels, my bags did not expand; in fact, they shrunk, as I finished one 900-page book and several celebrity mags. (So glad Jen dumped John.) However, when I approached the gate agent, I was told that — not again! — I had to check my bags. I went through the whole mime of how my bag fit in the container adding that I flew down with them as carry-on and I should be allowed to return with them as carry-on. The agent was curt and unforgiving, continuing to push me to check them. Eventually, I was tired of arguing and just walked on, tossing out the same rejoinder: If they don’t fit, I’ll check them.The plane was nearly empty; I could have carried-on an elephant and found bin space for it.
I am only speculating, of course, that the Spirit agents were pressing me to check my bags for monetary reasons. And I know this reads cynically; maybe they were just concerned about my leg space. But I have flown this airline pre-baggage fees and received no comments about my carry-ons.
All I can hope is that we who travel light don’t get penalized for going carry-on only. - entire post here