To be honest it is hard to prove Match Fixing and spot fixing without audio, video evidence or a money trail showing funds received, transferred for certain act, defendants in court will have a field day trying to prove that the evidence fails to satisfy the standard "beyond a reasonable doubt".
The way Cairns has now gone into hiding that his legal troubles are over is very telling. If he was totally innocent and if the charges were fabricated, he would hold his head high in public and even fight to stay involved in the only thing he knows i.e. Cricket.
If someone accused me of a crime of which i know is completely fabricated, false, i would aggressively shout, scream in the media from the beginning to the end at every possible opportunity to proclaim my innocence. Cairns appears to have gotten away with it twice due to smart lawyers and legal loop holes and is clearly playing it safe knowing he will not get lucky the third time around.