Why It Makes No Economic Sense To Gate-Check Your Carry-On Bag

I'm reticent to enter the "how my travel story applies to you" chorus, but as a markets reporter interested in how people respond to incentives and how businesses wield power over human incentive structures, I simply can't resist.

This weekend I took a relatively full United flight from Denver back to New York City. Sensing that we'd be packed from cockpit to bathroom, eager passengers began to coalesce around the gate door (comically early, of course).

You probably know how this goes. Throughout this process, we inauspicious members of "boarding zone five" were told repeatedly over the loudspeaker that this was indeed a full flight, and that our rollaboard suitcases had little chance of finding a home in the plane's overhead compartments.

But fear not, United then told us, because the gate agent would be happy to check our bag right there. We could pick them up at baggage claim back in New York.

"No, customers are not guaranteed [an overhead] space. However, if the carry-on bag is within the size limits we will gate check the item free of charge," United spokesman Charles Hobart confirmed to Business Insider in an email.

United was true to its word, and to the utter disbelief of rational decision-making passengers, a handful of our zone five comrades opted to gate-check their bags. This was the wrong decision (for them). Very wrong. It shouldn't take a markets reporter to tell you why.

It is downright silly to gate-check your bag. Do not do this unless you are a sucker, because you have absolutely no incentive to do so.*

Let's assume you don't want to check your bag because A) if you had wanted to, you would have done it already while checking in, B) it's your carry-on bag, meant for carrying on and C) who wants to wait at baggage claim in New York?

We don't have to yank out a Nash equilibrium to figure out how you beat United every time. If you're a zone fiver, you should opt-out of the gate check option and take your bag on the plane to find a spot. If you don't find an overhead spot, hey, whatever, United just gate-checks your bag anyway (per their free of charge policy).

Airlines like United obviously offer this gambit to save time, in the hopes that zone fivers will lose heart and just oh well the whole thing. Most people don't want to be "that guy" slowing down the plane for everyone (which is, on average, a pretty rare occurrence). This probably makes things easier for the boarding process.

There are two ways to look at why the economically-minded people at United do this. Either they don't actually care whether zone fivers bring their bag on the plane or not or they are just doing it wrong.

Let's say for a second that United does care. They really want you to gate-check your bag because it saves them time (and money). They're not asking just for funsies. If this is the case, they are doing it wrong.

If I were a United executive, here would be my policy. "OK, zone five, you have a choice. We can gate-check your bag for free now or you can risk taking it on the plane. But if you can't find a spot and we end up needing to gate-check it after all, you don't get a free soft drink or peanuts on board."

See? Now we're talking. Now I have a choice to make. And now, perhaps, this layover becomes a fun game of chicken with the other passengers.

But my hunch is that United really doesn't care all that much. Sure, it would be nice to speed things along and have the zone fivers willfully gate-check. Boarding goes faster and flight attendants have less bag tetris to do. But it doesn't really affect the bottom line, which is why they're kind of blasé about it over the loudspeaker.

Which brings me back to my original point. You have no reason to gate-check your bag. So, be strong, and don't.

*Caveats:

• This applies to the kind of gate-checking that requires you to wait to pick up your bag at baggage claim, not plane side.
• There's always the possibility you do find a spot, but it's well behind your seat in the cabin, forcing you to swim upstream at the end of the flight to retrieve it as passengers deplane. Anecdotally, I think it's still quicker to do this than to wait at baggage claim. But if you have a connecting flight with a quick layover, it could possibly make sense to gate-check it to your final destination if you really have to get off the plane as quickly as possible. The flight I was on landed at midnight, so these people weren't trying to make connections.