That seems kind of pathetic to me... You'd risk losing a friend (maybe one of your closest friends at that) in order to achieve a silver crown by your name by selling out to Jagex? All in all, It depends on how much respect and/pr loyalty you have for the player in question. If you value their friendship, then you should probably just forget about the multi-logging, and forget it's happening. If you value the Rules more than the player, then you probably should report, or at least do something about it. As another person said earlier on, you shouldn't let someone make the decision for you. It's your choice.