Why do people do this? I'm not referring to little old ladies needing help to stow reasonably sized carry-ons in the overhead, I'm talking about "carry-ons" (really, wheeled suitcases) that are so heavy you need two adults to lift it.

Here's an example:

US Airways 757 flight from PHL to PIT last week

This was a full flight, and as usual, it takes far too long to board because everyone is trying to squeeze their wheeled suitcases into the overhead bins rather than checking them into the cargo hold.

Normally I take a window seat for three reasons: 1) look out the window; 2) not have to get up to let someone else out (I only need to use the restroom on long flights); and 3) to avoid being bonked in the head by falling luggage.

My 9 year old son was hit on the head by falling luggage last June and went to the ER in San Diego as a result. He's OK, but I'm still kinda p.o.'ed that I lost $1,500 and a day of vacation as a result.

Anyway, on this US flight I got a middle seat assignment. I thought to myself, "Well, it's better than an aisle seat."

When I boarded the plane, I saw a woman sitting in the middle seat and a baby in a car seat in the window seat. Apparently she had selected aisle and window seat assignments with no intention of actually sitting the aisle seat. If she had chosen window and middle, I could have chosen a genuine middle seat and let someone else sit in the aisle seat. What is the point of letting people choose seat assignments they have no intention of using? I would prefer Southwest's open seating over seat games!

After I sat down in my re-assigned aisle seat, I saw a young woman trying to get her wheeled suitcase in the overhead bin. Her suitcase was so heavy, she could barely lift it off the floor! What did she put in there, osmium bricks?

A man offered to help her stow it in the overhead bin, so both of them try to lift it up. They didn't get a good enough grip and almost dropped it on my head!!!

Rather than continuing to sit and risk getting hurt, I unbuckled my seat belt and stood up while saying "Let me get out of the way to avoid a head injury from your suitcase that is too ****ing heavy." I stood by and watched them finally heave the thing up and into the overhead bin.

Please, people, do not help others stow luggage that is dangerously heavy in the overheads! All you do is encourage more people to bring heavy luggage.

Heavy luggage takes a lot of time to stow, will cause injury should it fall on the person sitting in the aisle seat, and if the total weight in the overhead bin exceeds its design limits, it may break apart in a rough landing, injuring several people.

I know airlines have gotten really cheap lately, but guess what, they still have these relics of the past called "baggage handlers" who will be happy to stow your suitcase in the cargo hold.

I checked my suitcase, and as usual, it arrived at my destination the same time I did. It is of legal size to be brought aboard, but I choose not to inconvenience everyone else and risk head injuries by letting the baggage handlers do their job. I bring valuables on the plane and risk losing my dirty underwear in the cargo hold.

I wish the FAA would institute the 8 kilogram carry-on limit seen in much of the rest of the world. Our flights could board faster, which reduces turn times and delays, thus improving aircraft utilization, and people wouldn't be going to the ER nearly as often when it's time to deplane.

If it's too heavy for you to lift, it's not really a carry-on, is it?