Gaelic Football Hardmen.
Some years ago, a local championship match was played in Tyrone. By all accounts, it was an incredibly hard-fought affair, and towards the end, neither team had a sub remaining.
One team had a full forward, limping heavily, and good for nothing. The only possible sub was a blood sub. So he asked the other full forward, his team mate, to punch him in the face. After a few attempts to get the blood going, our hero eventually retires with a broken nose. A sub appears. All is well until; the after match report, and I think that the result was declared invalid, and the match rescheduled.
It's worth mentioning that GAA is an amateur sport, and it was an under 18's match.