Recently, the Houston Astros were caught — and sort-of punished for — stealing other teams’ signs using live video from the club’s video room, which was supposed to be used strictly for replay review purposes.
Stealing signs has been happening since baseball’s beginnings, looked on as getting an edge on your opponent. It’s always been acceptable if done via the “eye test.” In other words, if a player or coach on the field can decipher signs using his own eyes, and relay them to a hitter, that’s seen to be part of gamesmanship. Some players and coaches are better than others at doing this.