I was informed that all participants should not wear clothing that include logos. This may include but is not limited to: clothing brand logos, business logos, and local school logos.
This is from the Guinness Book of World Records. If you happen to be in a photo, and you're wearing a logo that isn't pertaining to The Great Cloth Diaper Change or cloth diapers in general-- that photo cannot be used.
Someone asked me this: Logos such as, "World's Best Grandpa," etc. should be fine. =] We like logos like that!