"Armageddon" and "best of three" options ?

Now that refusing a single rematch has become the majority behaviour and fashion on chess.com, I'm still a little wary of the question: was your opponent showing sportsmanship? When you win a single match with the whites and refuse the rematch with the blacks, are you showing sportsmanship? Perhaps in this case, chess.com should offer a "single match" option for players who prefer this formula, with an armaggedon-style calculation of points and game times?  To my knowledge, there is no live competition where you can refuse a return match with black after winning with white. Similarly, a 'best of three' option should be offered to the other players. I don't think it would be technically very complicated. 

This is a very good idea. I am also tired of these, quickly gone types.