My thoughts on the subject: don't do it.
I've walked to school every day this semester, and on average, I've been yelled at about 3 times a day. It ranges from pointless: "Your hair is pink!" to disgusting and creepy and sexual. Just because I'm walking to school. Chill dudes. I'm sure my flat chest, Power Ranger's backpack, and shiny velcro shoes really do it for you, but chill.
Really, I see no need for it. Unless someone's saying, "Watch out for that bus!" (in which case, they'll probably keep their mouths shut.)