You are at your children's lessons? I mean not just physically being there, but actually watching your children.
I was watching my 4 year old in his karate class tonight and as I looked around I noticed that of the 8 other parents that were there....I was the only one paying attention to what the kids were doing. EVERYother parent was playing on their cell phone nearly the whole time. I know there are always exceptions for needing to use your phone...but I think barring anything major that the parents attention should be on their child.
Our daughter dances 20 hours per week. I watch a lot, but not every minute. I am also president of the booster club for her team, so I spend a lot of time chatting with people about booster stuff. I do not spend time on my phone though. And unlike a lot of other moms, I do not leave the studio. I don't see anything wrong with it though.
While at my daughters piano lessons, I usually have my phone up because I'm constantly taking pictures of her learning. At my sons practice, I'm the team mom so I am either talking to parents, spraying bug spray on the boys or cheering for them as if it was a game going on lol. When my daughter was taking karate, I would be on my phone or reading a magazine because they practiced where we couldn't see them. You have to at least give parents credit for keeping their kids active and taking them to their activities instead of just keeping them home not doing anything but watching TV, even if the parents are on their cells, at least they are there.