There are many ways of investigating match fixing but a common misconception seems to be people thinking they can spot match fixing from watching the game. The fact is, sport throws up all kinds of events and if people cried match-fixing every time, we'd be investigating even more sportsmen. It's usually punters who are losing that complain that a certain player has been match fixing. But they don't finger anyone when their bet wins. In reality, match fixing is subtle. Why would a player be so blatant? These guys in the IPL have been discovered through the Police not because someone's said 'Sreesanth bowled a dodgy no ball!'.
Kieron Pollard recently dropped three catches in three balls (75%, 80% and 95%).
Chances of happening based on my probabilities? 25% - 4.0 x 20% - 5.0 x 5% -20.0 = 400s. See it's not that incredible! But people say to themselves - what are the chances of him dropping three in three balls..must be millions! But of course Pollard didn't know he'd get three straight to him. A week later, he hits 68 of 27 balls and wins the game for his team.
Here's a Moldovan goalkeeper making an absolute plonker of himself which again got some match-fixing comments on Twitter
http://www.youtube.com/watch?v=JOOsI0NQExo (someone find me Dave Beasant's one because I'm sure he did something similar!)
and here is Rocky Baptiste's famous miss
There are a thousand examples. I agree it's tempting to think the only possible reason the player could have acted in such a way is if he was match fixing. Trust me, match fixers are far more subtle. Except when they're stupid.
There are over ten million sporting contests happening each year which can be bet on. Just remember, on the most basic probability level, something similar to Kieron Pollard is going to happen one in 25,000 times (not quite correct but I am no Ramanujan). How many contests do you view a week or read about? If it's 1000 a week and you're crying match fixing more than twice a year think again!