This will be my third year taking DS13 - so we started going when he was 11. Over the past couple years we noticed that some scare actors would back right off when they saw the kids, a few did not.
Last year we couldn't believe how many little kids there were - it didn't necessarily effect our evening, just thought it was odd (and potentially dangerous with people running all over the place).
My issue really was with teens - specifically teens that get dropped off at the front gate and have no supervision. I wish that under 18 (or an age near that) would require adult supervision. We had no problems with young kids - no problems with drunks - but got nailed a few times by groups of teens running from everything
Also, since we're talking about kids, realize just how much they will absorb while they're waiting in all of the lines. It's a pretty serious party atmosphere and we know that going in - lots of drinking and smoking in lines - adult conversations, etc. I have no issues with it (hey, it's an adult event), but like to let others know what the evening is like.
A side note, for noise, we ordered cool earplugs off of Amazon. We saw our RIP tour guides using them our first year - best purchase ever for DS13!