The usual examples we give for the law of unforeseen consequences involve government intervention. For example, rent control helps people who manage to get apartments at subsidized rates. But supply dries up so many people won’t manage to rent. (They will buy a house they can’t afford and cause a mortgage crisis!) But the law of unforeseen consequences should equally apply to the private sector. There is less scrutiny of the private sector by the media. Plus it is hard to get information as it is not in the public domain. Sometimes, the policies adopted by forms are public and we can all see the law operate:

An entire cottage industry has emerged for products that help people evade the baggage-check fees, according to Kate Hanni, director of, a consumer group that represents airline passengers. Ms. Hanni uses vacuum-seal bags inside her carry-on bags, she said; the bags, which shrink down to a compact package when air is pulled out by a vacuum cleaner, allow her to fit considerably more items in a carry-on than would normally be possible.

“I can fit three times the amount of clothes in a carry-on than I used to be able to,” she said.

There is also the Scottevest line of travel clothing in which trench coats, vests and other garments are made with large built-in pockets that allow people to carry everything from folded shirts to an iPad.

“You can fit all of your folded shirts, iPad, cellphone, iPod, sunglasses, camera, passport, keys — you can put everything in the jacket that you would put in a carry-on,” Ms. Hanni said. “It’s sort of sweet justice.”

Plus we have more people with carry ons, delays as they board the plane and gate check their bags etc. etc. Surely, some effects were foreseen but were they all?