Thumbs up for keeping busy. I used to do some of my "real" work while I semi-watched the girls' synchro practices. Have laptop, will travel.
I don't like to leave the rink, although I have run chores at times. I always make sure my kids knew where I was going, when I'd be back and that they had my cell number. It's more of an issue with little ones or kids who don't have buddies at the rink. I've "rescued" more than one 7-year old who couldn't find mom/dad and started panicking. Friends are a convenient distraction, but if they don't know anyone else, little kids get nervous.
I've also cleaned my car out while I wait - it's one of the few times where there aren't three or four skating bags in the trunk.
I pack a tote with my dustbuster, window cleaning stuff, and newspaper or paper towels and go to town once the kids are in the program.
One mom used to knit constantly and she stayed in to chat while she worked on her project. (Heat and a/c is a good thing.)
I've done handwork (sewing trim, shortening skirts) on skating outfits and mended tights while I waited.
At day camps, they really don't expect the parents to stay and wait/watch.