Wac, I guess I could understand where you are coming from. Bigs hit it on the head, witnessing horses breaking down (also you make it seems like a daily occurance. It was 2 very unfortunate incidents that occured in the stretch {even worse}) is definitely on the bottom of the long long list of things you have/should worry about shielding your children from.
My son just turned 6 and I take him to Monmouth and Freehold
all the time. He will make his first visit to Saratoga this summer. He doesn't get dragged there and when he's ready to go we leave. He enjoys seeing the horses in the paddock and watching the races with his daddy. He also likes to do all the kids stuff when they offer it on Sundays. I try to teach him little things about racing.
Thankfully I don't remember seeing anything tragic happen with him when we have been at the track. Unfortunately we have seen a couple of spills on TV and I'll admit that I really didn't explain it to it's fullest extent. Reasons being, I didn't know the full extent of the spill and more importantly I didn't feel the need of having the death/heaven talk with my son yet. He's pretty sharp and asks questions about heaven and his deceased Grandfather, so I think he has an idea. But I remember being afraid of death as a kid and I don't want my 6 year old to start asking questions or thinking about it now. It's one of those things I will worry about if it God forbid happens while we are there.
But to prevent my son from going to the track and spending the day with his father because of something that probably won't occur seems over the top to me. You will see one day, that there are just too many other real things that they need to be protected from. Instead of a nice day at the track with his old man.