chip-rider

One who attends dining excursions with friends only to eat the complimentary chips and salsa provided by the restaurant (usually Mexican)

Waitress 1: "and you sir?"
Brett: "Im good with just a water, thanks"

*back in the kitchen*

Waitress 1: "We got a chip-rider on table five"
Waitress 2: "Spit in it, you know they aint gunna tip"

"Another God damned chip-rider!"