I suppose this tells us that some schools are more welcoming of police enforcement on their campuses than others that likely prefer to handle such matters internally. There has to be a story behind the Haverford stat. For small LACs an isolated incident (an out-of-hand party maybe) could dramatically skew these results and in many cases these results indicate that fewer than 1 arrest per year. My guess is that the arrests are a result of more than simply underage drinking in many/most cases.