I would honestly be surprised if the umpires got more calls wrong considering how often they get simple decisions wrong now.
When you have clear evidence of inconsistent umpiring, inconsistent MRO rulings, inconsistent tribunal decisions (not to mention those that do not survive independent review) and compromised fixturing, it's fairly obvious that getting things right is not a priority with the AFL.
I refuse to accept that over a 15 year period, the slime have amassed over 900 free kicks more than they have given away, can be explained by umpires making genuine errors of judgement. The next best team is North Melbourne with a 300+ free kick advantage over the same period.
You might get away with putting it down to genuine errors in a few games, perhaps even a season but no way is it genuine when it is sustained over 15 years and that period of dominance started a few years after Gieschen took over as the umpire's boss.
Throw in Fisher's regular performances including 14 frees against Freo and 0 for in a game against St Kilda at Docklands or Margetts / Farmer's performances in slime games to the point that last year they were no longer allowed to umpire the slime.
You can put up the contention that these are all genuine errors but nobody with a clue would accept that.
Friday night's game was umpired utterly inconsistently with very similar occurrences getting completely different decisions.
