Yes, this is actually happening!
From the New York Times:
WASHINGTON — For decades, spying on another team has been as much a part of baseball’s gamesmanship as brushback pitches and hard slides. The Boston Red Sox have apparently added a modern — and illicit — twist: They used an Apple Watch to gain an advantage against the Yankees and other teams.
Investigators for Major League Baseball have determined that the Red Sox, who are in first place in the American League East and very 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 baseball inquiry began about two weeks ago, after the Yankees’ general manager, Brian Cashman, filed a detailed complaint with the commissioner’s office that included video the Yankees shot of the Red Sox dugout during a three-game series between the two teams in Boston last month.
The Yankees, who had long been suspicious of the Red Sox’ stealing catchers’ signs in Fenway Park, contended the video showed a member of the Red Sox training staff looking at his Apple Watch in the dugout. The trainer then relayed a message to other players in the dugout, who, in turn, would signal teammates on the field about the type of pitch that was about to be thrown, according to the people familiar with the case.
Baseball investigators corroborated the Yankees’ claims based on video the commissioner’s office uses for instant replay and broadcasts, the people said. The commissioner’s office then confronted the Red Sox, who admitted that their trainers had received signals from video replay personnel and then relayed that information to Red Sox players — an operation that had been in place for at least several weeks.
The Red Sox responded in kind on Tuesday, filing a complaint against the Yankees claiming that the team uses a camera from its YES television network exclusively to steal signs during games, an assertion the Yankees denied.