I had a heated discussion about this with someone the other day.
Here's the situation: You are playing a friendly stock match of Super Smash Bros, or similar life-based game, against one other person. This person just so happens to mistakenly run off the stage and/or fail an easy recovery. Assuming lives, skill level, and damage are more or less equal at time of death...
Do you:
A. Take advantage of the situation, because it's their own stupid fault
or
B. Take one of your own lives, because otherwise the game is uninteresting.
Comments
The only exception is when mocking an opponent by killing myself purposefully.
A true test is if said person who screwed up ends up recovering and winning the match.