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.
Warm colors like brown and orange indicate higher wind speeds. Cool colors like purple and blue indicate lower wind speeds. You can select different overlays based on the particular hub height you are interested in: 20 meters, 50 meters, and 80 meters. In some high latitude areas in the Northern Hemisphere, and near coastal regions, you may notice some sharp color changes. If you zoom in on these locations, you will notice these sharp color changes eventually disappear.