It's true - the person who checks your card and asks you whether you have any weapons in your bags is not a United employee. She cannot change reservations.

It's also the case that the RCC staff also have other duties - the same people work the transfer desk, are GAs for the flights, and greet the inbound aircraft. One could certainly make the argument for more staff at peak periods.

That said, my experience with the FRA RCC staff has always been very positive. They've always taken care of me. No matter how mangled my reservation has become, they have always gotten me where I needed to go. I've found them always to be friendly and polite.