Besides, if MS can't code their damn store software properly, they have bigger problems than giving out unintentional free games and LIVE service...

There is morality and then there is aesthetics... Morality is black/white (well, in my mind. Rape is a immoral because it's initiated violence, and it's ridiculous to claim to have raped in self-defense). Aesthetics are the gray areas, and even cultural and more trivial social norms like etiquette, politeness etc. They also cover mentioning when you get too much change, sending a email to MS about the OP scenario, or even trying to take advantage of it and so forth. There is a clear division between them.