Over the years my experience with Warped Tour has changed and evolved. I began attending as a young teenager, barely phased by the heat and crowds. As I got older I found shade in the less-crowded 21 and over tent, even if I was just drinking water. Now as a parent, I have made note of the family-friendly aspects of the event as well. While the Irvine city council may think it's a recipe for disaster, I think it's a great bonding experience for parents and kids of all ages.
For younger kids, heading into the crowd in front of the stage isn't really an option. There's plenty of room to watch the show from the back of the crowd, but if it gets too overwhelming, you can walk around and check out some of the other offerings. To keep cool in the heat, they offer shade tents throughout the venue, misting stations, free water refilling stations sponsored by Kleen Kanteen, and my personal favorite is the huge inflatable slip and slide they have every year. There are also all kinds of vendors throughout the area, some which offer kid-friendly fun and games. Truth (yes, the anti-smoking organization) is always there playing games and giving out prizes to participants.