The Griff Rule is a term that appears to be limited to a single definition on Urban Dictionary. According to this definition, the Griff Rule is a social experiment that has been proven to show that people will only come to another persons aid or help them when the situation is beneficial. However, there is no further information or context provided to explain what this social experiment entails or how it was conducted. It is possible that the term is used in other contexts or fields, but this definition is the only one that appears in the search results.