Normally I would say it were inappropriate. After working the Susan G Komen - Race for the Cure Southern Nevada for the last 7 (or so) years, I am okay with it. People of all ages can get breast cancer, male & female. Granted, it is more prominent in adult women, anyone can get it.
I see it all! I am able to identify survivor's by their pink shirts. I have seen men wearing them, many grandma's, mom's of brand new babies, and young, young, girls. I can identify those celebrating survival and those memorializing by the signs they hold and wear. It is one of my most painful days of the year and nothing hurts my heart more than to see a stroller go by with a sign that says, "In memory of Mom", with Dad pushing it alone.
I have had the hair on the back of my neck stand up during the race, as their is so much energy surrounding us. I have touched survivor's to ask if it is okay to take their picture and have them turn to me with their eye's loaded with tears and reach out for a hug, as they realize how close to death they may have come.
They have come up with all kinds of creative slogans because the boobs are rather endangered. In fact, you would be surprised at the amount of people who surround you have/had breast cancer and no longer have their breasts and/or nipples. Yep that's right, the nipples are a source of cancer too and sometimes they have to be removed. So you never know why any child is wearing such an advertisement and if it is just for fun, I see it as a donation toward a good cause and good awareness.
Please open your mind to this and don't look down on anyone wearing these bracelets. It maybe their constant reminder of their mother or other loved one.
(By the way, our time is volunteered)
*Edit
After reading the other responses that say they should be aware of what they are wearing, what an awful thing to be questioned about. I hope no one asks a young man why he is wearing a bracelet...to find he lost his mother after 5+ years of battle with treatment. What a sore spot with me!