Holy crap! I haven’t watched the US Open (or any tennis tournament coverage) in ages. Twitter seems to be in news everywhere and the Open is no exception. The U.S. Open, which gets set to start on Monday, has issued a warning to players and their entourages to be careful about what they post on the social networking site.

Signs are being posted in the players’ lounge, locker rooms and referee’s office at the USTA Billie Jean King National Tennis Center with the header: “Important. Player Notice. Twitter Warning.” They also warn about using Twitter away from the court, saying sending “certain sensitive information concerning your match or other matches and/or players should be avoided. Depending on the information sent out this could be determined as the passing of ‘inside information.”‘

The messages define that as “information about the likely participation or likely performance of a player in an event or concerning the weather, court conditions, status, outcome or any other aspect of an event which is known by a Covered Person and is not information in the public domain.” The warnings say they apply to players, coaches, agents, family members and tournament staff.