So, how is this working out? How does human behavior factor in? Here's one story.
Last night, I flew on an American flight from St. Louis back to San
Francisco. The in-bound connecting flight from Miami was two hours
late. Thus, all 152 passengers were ready and eager when it finally
came to board the flight (the plane was a single-aisle 757).
It took 40 minutes to get all of the passengers on. Why so long? Since passengers didn't want to check their luggage, they brought larger than usual bags on the flight. Since there's only so much overhead storage space, it took passengers longer to rearrange the bags in the over-head space so they could get their bags to fit. And, of course, they did this while they were standing in the aisle so that no one could pass them.
Here's the juicy unintended consequence: since we pulled out so late, the pilot came on and said, "We'll try to speed things up for you, and fly a little faster to make up up some of the time we lost getting out of the gate."
So, in effect, American's new checked bag policy ended up costing them money in extra jet-fuel use. Wow!
QUESTION: What unintended consequences have you noticed lately?