I think the dilemma involves getting something you (will) want (if not now then in some future), from someone else/others and taking this into account in general decision making. This is not about being sadist or saint, it is also not about opportunistic behaviour but more general decision making. So to say “no one will remember” is odd: who are you being cruel -or kind- to if not the victim/beneficiary of your choice, why should this pattern go unnoticed over the long term?