It's actually more common than you might think. Being a high school senior myself and someone who tends to pay very close attention to my surroundings I do gather some information about relationships. I've also been to 4 different High Schools so my data is quite spread out. I've came to the conclusion that, in many cases, older males of mediocre social status tend to date younger women, usually between 8-10th grades, with enough frequency that it is almost surely happening in any given school at any given time. Simply stated, it is a mutual benefit for both parties, the female gaining superior social status, and the male being able to date a female that would, in normal high school dynamics, be "out of his league". It's by no means uncommon and by that benchmark, amoral.