My dogs love kids so much that before a child has an opportunity to ask if they can pet my boys, they are usually mauled over and laying on the ground receiving lots of puppy kisses. We are working on this
I'm also grateful that my boys are too big for children to pick them up.
In Copper's case you may want to make sure it's him doing the approaching rather than the child. Also, just reading Britster's comment, perhaps you can bring treats with you and let the kids offer them to Copper.
(oops not sure how that sleepy face got there!)