A report released by Michael S. Schmidt of the New York Times on Tuesday revealed that the Boston Red Sox used an Apple Watch to steal signs from the New York Yankees during the 2017 regular season:
"Investigators for Major League Baseball have determined that the Boston Red Sox, who are in first place in the American League East and likely headed to the playoffs, executed a scheme to illicitly steal hand signals from opponents’ catchers in games against the second-place Yankees and other teams, according to several people briefed on the matter."
The "scheme" was noticed by the Yankees, a few weeks ago when they noticed a member of Boston's training staff looking at his Apple Watch in the Red Sox dugout and then giving players information.
Most likely, the intel given was signals relayed from the catcher to pitcher, which would allow the opposing batter to know what was coming.
After a two-week investigation, Major League Baseball went to the Red Sox with the information found. The club in fact admitted to the wrongdoings, stating they used images from video replay personnel.
A penalty, if any, is unknown at the time. Stealing signs has been a fixture in baseball for most of its existence, which dates back almost 200 years.
But the Yankees might not be the absolute victims here. Schmidt also reported that the Red Sox filed a complaint against the Bronx Bombers, claiming they used cameras from the YES Network broadcast to steal signs.