If you don’t know when you are wearing the smartwatch too close to the players it actually violates the sport’s rule in MLB. So the same problem got MLB coach because he was wearing an Apple Watch in the dugout. Reach is actually too close to the players.
We are talking about Ariel Prieto which is Arizona Diamondbacks coach. MLB have additionally investigated coach’s watch including smartphone, but eventually they did not found anything suspicious. Because it was innocent mistake.