News is trickling out of the Billie Jean King National Tennis Center that cautionary signs now litter locker rooms and players' lounges, while emails to all players with similar strict messages have been sent out. On top of forbidding tweeting on the court during matches, players, coaches, agents, and family members are being instructed to keep their off-court Twittering to an absolute minimum.
The big concern is over tennis gambling and how tweets could potentially be construed as sharing insider information, which is strictly forbidden. The signs posted around the facility indicate that the Tennis Integrity Unity will be proactively monitoring tweets for "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."
According to the Telegraph, Jeff Ress, formerly of Scotland Yard, also emailed players with a warning that had a headline of, "Important player notice – Twitter warning," and "informed players that they should not be sending 'tweets' that include "sensitive information" which relates to their own matches, or to other players and their matches."
Unlike the SEC ban of social media from college stadiums, which was later revised, the US Open doesn't seem to be taking a stance against fan involvement and content sharing via social media. In fact, the official website even includes a fan zone, and links to their official Twitter account and Facebook Page.