Need Pin trading etiquette with kids please!

[Simba's Mom]

I enjoy pin trading with CMs when I go to WDW, and have a bunch of "traders" just for the sake of the fun of trading. I'd love to trade with kids too-I hear they enjoy it and sometimes you get some great comments from kids. Like one time,while I was standing waiting for the restroom and it was pouring rain out. Well, all this little girl in front of me could think of was how disappointed she was that she hadn't seen much of the characters! And her poor mother was trying to explain that since it was so rainy, the characters didn't want to get wet. Well, it was so funny because this little girl just did not understand why "a little rain" should stop Mickey and Minnie (can you tell I can't wait to be a Grandma?) So I'd love to trade with the children but I certainly don't want to frighten anyone when an adult (usually I'm traveling alone besides) comes up and starts talking to a child. But I'm afraid if I approach Mom or Dad first, the child will feel insulted that I'm not addressing them. All I want to do is trade any pin on my lanyard for any pin they want to trade. How can I best do this? Could a parent give me Pin Trading with Kids Tips?