Prices matter: luggage edition

Imagine the surprise of the airlines when they started charging for checked bags but not carry-on bags! People started carrying-on more bags. Who could have predicted this? Surely there is some model about to capture this odd behavior.

For me at least, one of the two main values of being a frequent flyer on Delta is getting to board early, which implies not having to worry about overhead bin space (the other is sometimes getting to sit in the front). The frequent flyer miles themselves are a distant third.

Of course, I never checked bags unless I absolutely had to, even without the fees, because it sucks up an extra 20-30 minutes at the end of the flight and runs the risk of damage or loss of the bag.