GHSA Golf Rules: Section 6, B-2, p. 75
2. Range finders and GPS devices will be allowed in match and tournament play with the following stipulations: (a) In each grouping (2-4 players), if any player uses a “range finder” then all players will have access to the distance information. (b) Any player using a device who does not share the distance information with other players in his grouping, when asked, will be subject to disqualification for a serious breach of etiquette. (c) GPS devices on cell phones or wrist watches are NOT permitted under penalty of disqualification. (d) Range finders that calculate slope, wind or other information are NOT permitted under penalty of disqualification. (e) Single function GPS devices that measure distance only are allowed. Any device that performs multiple functions is illegal and their usage will lead to disqualification.