I hate to say it, but it might just be a local thing. USAir in CLT, LGA, JFK, MCO, and any other large airport have all been accommodating without any prior reservation. I just walk up to the gate and ask.

Now with MYR you might be running into a multi-agent. One that has more to do then run the gate and may be too busy to deal with any pilots and "free" rides to work.

If your in-and-out of MYR alot bring them a treat/ snack and they'll remember you.....don't forget the flight crew snack either