Wirelessly posted (Treo 650: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98; PalmSource/Palm-D060; Blazer/4.5) 16;320x320)

Why are people asked to re-check at the gate? I had about 9 people on my BOS-IAH flight asked to re-check at the gate. I wasn't sitting close enough to see if they were non-revs but it appeared to be a pretty diverse group.

Seats being assigned. Upgrades being issued. Standbys clearing.

I'm sure there are other reasons, too.

Also guessing it may have been people who checked in online, did not check luggage, so they had no way to validate they were actually at the airport. So for standbys, upgrades, etc. they need to know who is really there.

Aircraft swap, seat assignment changes?

Some good GAs will even spread people around if the load is light, to give people empty middles and such.

I check in online all the time without checking luggage and never have been called to the podium unless it was for an upgrade.

Nope, the process doesn't work like that. But like others have said, there are plenty of reasons to call. All the reasons mentioned in other posts, but there are also incidentals. Ex: getting a call from the inbound a/c warning that a pax in seat X got a little ...queezy... during the flight, and thus, call the passenger on the outbound to have them re-sat.

So, ~10 re-checks on a flight? Not that surprising. Now if 1/2 the plane were called, I'd assume otherwise... :)

re-checks
 

Sometimes they do it in order to seat 2 passengers together.

It seems like whenever I get 1B, they always ask me to move some 2 other passengers who don't plan their travel as well as I do can sit together.