Well, if it's a cash tip, I hope a top-knotch server keeps the extra part for herself. Can't track cash so that's advantageous for a great server.
Great, you can hope. You have no actual control over where the money ends up. If a server gets a reputation for being chintzy with the tip-outs, guess whose food will be lukewarm and slow, guess whose tables won't get bussed and guess whose drinks will be watery.
A truly top-notch server would probably be extra generous with the tip-outs, just so they can continue to provide top-notch service to the customers. Hot food, timely, efficient service, fast table bussing and great drinks.