I remember in high school coaches had stupid rules like this and encouraged us to focus on the race at the meet. There is no benefit to overthinking things right before you race or day of. You should have done all that days in advance. It's much more important to relax. If someone does that by watching videos on their phone, listening to music, or playing video games let them do it that way. What's important is when you toe the line you're physically and mentally ready to go. Different people do that different ways. A lot of athletes if you ask them to sit and focus on the race at the meet leading up to the race are just going to get their self too pumped on adrenaline too early or stressed out and negatively affect performance.
What do you think? As a high school coach, should I allow my boys to play video games just before warming up for their distance races or not? Seems to me they are not focusing on their race.
If you really take yourself seriously as an athlete and a runner, then you won't play video games before a race.