I would say, YES, take your child.
We don't have children but when I interviewed Brad prior to going to his classes one of the things I discussed with him was that both my husband and I wanted to come to the classes. We knew we'd both be equally involved in the raising of this puppy.
Brad was the only trainer that I spoke to that agreed that everyone who is in the family should get trained! Some of the programs I looked into would only allow one person to accompany the dog. Of course, Brad said, "That's hogwash!" (well ok he may have used some other word there...)
Anyway, subsequently we attended the street safety 8 week course here in Calgary and on several occasions brought with us our nephews (sometimes one sometimes both); they were 7 and 8 yrs old. The kids and their parents are the 2ndary care givers for our pet because my husband and I travel a lot.
And, BRAD was AMAZING with those kids!!!!!!!! They LOVED him. And, he used them to prove to the adults how easy it was to work with the dogs when following the correct procedures. The kids gave it their ALL and of course Brad always insists we bring our A game so he was happy with them.
It has been soooo very beneficial to the kids and our dog as a result because now there's consistency in methods and expectations no matter where Vegas is staying.
I think you'll be very happy you included your child (either in the 1 day seminar or the outdoor class if there is one afterward).
Enjoy!
Lynda