@ydl There are winners and losers in both scenarios. You scooping to your friend in the first round (even though you could argue that he should have won) very well could have kept someone else out of the top 8. I'd argue that the difference in your scenarios is the certainty of the outcome - both the certainty in what would happen if you played it out and the certainty in the outcome of your decision (that it kept someone out of the top 8).
@desolutionist That's what happened - Rich Shay came in 9th this most recent event. I'm not sure that it matters from an ethical standpoint if the person that was "harmed" by my decision is someone I know or someone I don't know. My justification for what I did is not based on utilitarianism. I just don't think I'm obligated to play a game of Magic for the purpose of knocking someone else out of top 8 contention for little in the way of prizes. To me, it's equivalent to scooping because my car wants to leave, scooping because I want to play in another event, or scooping because I have a migraine. This isn't like I'm a paid athlete where me performing is part of my job. It's a hobby. Does the reasoning behind the scoop alter the ethics if it doesn't change the results? That's my point of contention.