Playing Super Smash Bros. Brawl can be pretty competitive even if you're just playing with your friends, so imagine the pressure surrounding a match in the Major League Gaming circuit, the pinnacle of competitive gaming. The most recent MLG event saw two players supposedly succumb to such pressure, as Mew2King and ADHD were banned from future events for breaching MLG rules.
The official line from MLG is that the players broke the rules by “intentional Forfeiting or conspiring to manipulate Rankings or Brackets,” which translates as "match fixing". However, a blog post by ADHD explains his side of the story, and let's just say it doesn't do him any favours.
While I did offer to give him 300 dollars as a token as friendship because he had previously split with me when I was 2nd/3rd numerous tournaments in the past, it was not an intentional forfeit, rofl.
When I entered the ring (or stage if you must), Jason informed me that he was not playing well and he did not care of the result of the match. I said: "Alright, fine, let's just play it out."
Generally, giving money to competitors on a pro-gaming circuit as a "sign of friendship" isn't really a smart move, so it shouldn't be too much of a surprise that both players were banned from competition. Reflectzyn has the whole sorry tale, shedding light on the murky issue of splitting winnings in pro-gaming tournaments.