I can only imagine you are referring to a restaurant that advertises having curb service. I still cannont think of one that does enough of this that they would devote an employee to this only.
Example?
No, I've actually only had curb side once (at PF Changs). I know at Macaroni Grill on busy nights they have someone (or used to). A hostess would have to clock in under the server rate and spend her whole night just taking care of to-go orders. Chilli's and On the Border were like that too.
I used to work at Saltgrass Steakhouse (they don't exist up here, but they're in a different league than Outback and Tx Roadhouse, for the same price) and to-go's were all on the bartender, who also got paid like a server.
My knowledge is as current as when I was in the industry 8 years ago, so things at those places may have changed.