ST KILDA'S 15-point victory over North Melbourne at Carrara Stadium on Saturday was meritorious for all sorts of reasons.

The Saints came back from five goals down after a lamentable, goal-less first quarter in which they played the sort of introverted, dispirited football that has imperiled the finals chances of one of the pre-season favourites. Led by captain Nick Riewoldt, the Saints took chances, rediscovered their confidence and ran over the top of opponents noted in recent times for their ability to dig deep in pressure situations.

But, most notably, St Kilda won despite being the first team to be (correctly) penalised under the heavy-handed interchange regulations - a major hurdle given both the ridiculously punitive nature of the penalty and its unfortunate timing.

When Luke Ball stuck a toenail out of the interchange box moments before teammate Andrew McQualter left the field 14 minutes into the final quarter, the Saints had clawed their way back to a narrow lead and had the ball in attack. The subsequent goal kicked by Daniel Harris via the free kick from the centre of the ground plus the 50-metre penalty prescribed by the new rule not only put the Roos back in front, it could have deflated the Saints.

So to overcome the confusion created by the sudden entry of the emergency umpire, whose presence on the arena was only slightly less welcome than that of a streaker earlier in the game, was an indication of the strength of the Saints' resolve.

Victory meant St Kilda coach Ross Lyon spoke diplomatically about how the free kick had been a reminder of the new rule's consequences. In defeat, you suspect, his post-match press conference would have been R-rated.

As relieved as Lyon will be the AFL officials, whose hasty implementation of the rule had already created the embarrassment of the free kick and 50m penalty wrongly awarded in the Adelaide-West Coast match in round nine. That led to the removal of the widely ridiculed "Post-it Note rule" where clubs had to record changes on small pieces of paper before players could go on and off the ground.

The rule was imposed again yesterday with Melbourne the beneficiaries of a Brisbane mix-up. Given Paul Wheatley missed the shot and the Demons won by a point, the Lions might have felt disgruntled had they not been the beneficiaries of a number of line-ball decisions.

Inevitably, those defending the new rule will say that the clubs and players are aware of its consequences. But you might also say that if the death penalty were introduced for jay-walking, then those facing a lethal injection for putting a foot on the road with the little red man flashing knew the risks. Patently, the consequences of the interchange rules are absurdly disproportionate to the minor breaches they punish.

Like the failed hands-in-the-back rule, which has created a similar capacity to compromise the outcome of games for meaningless infringements, the interchange rule was a massive over-reaction to a minor problem highlighted by Swan Jesse White's early entry during the draw against North Melbourne. It was something that should merely have prompted the introduction of stiffer fines, not a punitive rule that will one day have unfortunate consequences.