Like notaries, witnesses aren't generally required in order for a contract to be legally enforceable. However, each state may require special kinds of contracts (e.g., real estate deals, wills, and marriage agreements) to be witnessed by a third party in order to be binding.
McDonald's, apparently, use red and yellow because red=fast and yellow=hunger (hence fast food!). Remember also that meaning is what we create. It does not exist in the color itself and individual meanings may or may not exist in different cultures and individuals.
FAST: FAST is a coalition of the Internet Advertising Bureau (), the ANA, and the ARF that has recommended or is working on guidelines for consumer privacy, ad models and creative formats, audience and ad impression measurement, and a standard reporting template together with a standard insertion order.