I once worked with one of his fellow umpires (boundary not field) who knew the "offender". In his words, not cheating just a massive "brain fade" (you should see all the free kicks that quarter - those two aren't even the worst!). A 300 plus game veteran - never umpired at senior level again and rightly soEvidence of cheating please.
We've all made casual wisecracks in the outer about umpires being paid off but surely you don't seriously believe there is systemic cheating?
If it's a choice between conspiracy or incompetence, back incompetence every time (a variation of Hanlon's Razor)