Last year my son was about 6 months old, exclusively breast-feeding, and I was attending the 2 day special needs course before the conference. That being said, I could not leave him at home with dh or other family members for that long, living in Alaska it took almost 2 days to get there and back, so that would have made for well over a week I would have been without my baby. I paid for my sister-in-law to fly with me from Seattle to Chicago and take care of my son while I was at the special needs course and the conference sessions. Since my hotel costs were covered with the grant funding we had to send me, all I had to pay for her was her flight (much cheaper for her to fly from Seattle than for my dh and older son to fly with me from Alaska). She and ds went all over Chicago every day while I was busy and they had a great time. She had to fly back to Seattle a day before I did, so I only had to worry about keeping my son with me that last day, but that wasn't too bad because there weren't any sessions that I absolutely wanted to go to without any distractions. He loved to be worn in a sling or wrap of some kind, so most of the time he was just snuggled up against me with no problems at all. At lunch that afternoon I sat with all the other techs from Alaska and everyone wanted to pass him around, so I didn't have to hold him by myself the whole time.
This year, I'm leaving everyone at home and going all by myself to the conference! I am very much looking forward to it. We were supposed to all come down as dh has family in Portland and we were going to go out to the Oregon coast after Lifesavers, but dh wasn't able to get the time off from work and plane ticket costs have gone through the roof from here, so our plans had to change. I would not bring my kids with me to the conference sessions the ages they are now. They would be totally bored and I would not be able to learn as much as I have without them there. It's like taking a kid with you to college classes or to the CPST course, it's not fair to the kid or everyone else that is paying to be there.
There are people there at the conference who aren't just CPST, there are police officers, public safety personnel, highway/traffic engineers, etc. The majority of people there are being sent by their employers and look forward to the chance to network and catch up with people they only get to see at this conference each year. I know many of them don't appreciate having a bunch of kids running around being a distraction.
If you absolutely must take your kids with you, be prepared to sit in the very back of the session or miss out on sessions to attend to their needs. Otherwise, arrange a sitter to spend the days with them or leave them at home. It's just inconsiderate for those attendees who have made other arrangements for their children.
Sorry if this is rambling quite a bit, I'm on very little sleep right now as I've had sick kids this week.