AITJ for secretly disabling my boyfriend's smart watch notifications during dinner with my family?

F26, my boyfriend is glued to his smart watch. Even when we go out, it buzzes nonstop with work emails, crypto alerts, random Discord pings. He swears he is listening, but mid sentence his eyes drop to his wrist. It drives me a little insane, but I usually just joke about it. Last weekend he met my parents for the first real family dinner. I had told him how important it was for me that he was present and tried to connect with them. He promised he would put his phone away, which he did, proudly putting it in his jacket. Five minutes into appetizers his watch started buzzing. He kept checking it under the table like a teenager. My mom noticed and got quieter, my dad started talking mostly to me. When he went to the bathroom, he left the watch on his chair. I opened the settings, turned on Do Not Disturb for the rest of the evening and put it back. When he came back, he looked a lot more relaxed, actually laughed at my dad's jokes and my mom later told me she finally saw "the real him". He never realized what I did. I told my sister later and she said it was a huge boundary issue, that I "trained" him like a child instead of communicating again. My view is that I had already communicated and just removed a distraction for a few hours. So, am I the jerk for touching his watch without asking, even if the result was positive for everyone?