Two players have been disqualified from Pro Tour–Valencia today. Rookie of the Year Sebastian Thaler and his countryman Klaus Jöns were both disqualified as a result of an incident in their match against each other.
Here's what Head Judge Jaap Brouwer had to say: "After interviewing the players, we discovered that they had agreed on a prize split at the beginning of the match. During the match, they discussed who would concede to whom, based on who had the better chance in the metagame." Conceding in the hopes of getting more money from a split qualifies as Bribery, leading to an investigation by the Head Judge and, in this case, the subsequent disqualification of the two involved players.
Jaap Brouwer and Riccardo Tessitori, his shadow judge (who is there both to learn from and advise the Head Judge), pointed out that "split plus concede is always bad and almost always leads to a DQ." Riccardo offered the pie metaphor: "Think of two ingredients that just don't go together very well."
Jaap went on to add: "Both splits and concessions are legal, but together, they are venom."
The other major issue leading to the disqualifications was an attempt by the two players to change the match results after the match was over, which is Cheating — Fraud according to the DCI Penalty Guidelines. If one player wants to concede, it must be done before the match concludes (that is, before the final game of the match ends); otherwise, it constitutes falsifying the results of the match.
Fraud and Bribery are each sufficient cause for disqualification.