But unlike most competitors, he can't go back at the end of the day and grumble about the injustice of it all to his nearest and dearest. That's because the official who imposed the sanction on him was his own mother, Kay.
The Kiwi nudged gate five during his run in the heats at the artificial rapids in Lee Valley, but rather than try to look the other way, kayaking official Kay Dawson gave the penalty without hesitation.
Dawson bravely pretended that he'd not expected any special treatment from his mother - and admitted that his error had been bad enough that he'd not really given her any hope of turning a blind eye.
"Fortunately it was definitely a genuine touch, and of course she called it right, as I'd expect her to," he said. "Though I'll be trying my hardest to keep mum unoccupied in my semi-final run."
It does seem an amazing conflict of interest - can you imagine Usain Bolt's mum deciding if he had false started in the 100m final?
But Kay Dawson, an experienced international judge and the only New Zealander serving as a gate judge at the Olympics, explained that she is deadly serious about how her responsibility to ensure fair play.
"I've been officiating for a number of years now and know a lot of the athletes, so it is easy to put aside any personal emotions when I'm on the course," she said before the competition.
"Several of the top men's slalom paddlers have stayed with us in New Zealand while they've been training with Mike and I owe it to all of them to do the most professional job possible."
All very well to say that, but what if things get close in the heat of competition during a gold medal run? Well, judges in kayaking have a system that while not foolproof, does create a system of accountability.
Each judge oversees a gate, but also looks at the two gates next to them and then reports to a chief judge, who oversees all judging and can overturn any call. This means every gate is being checked out by three people plus the chief judge.
As it happened, the penalty was irrelevant: Dawson came through his heat with four seconds to spare despite the penalty.
And there's no need to worry about any more potential conflicts: the New Zealander suffered a disastrous run in his semi-final on Wednesday morning, completely missing out two gates to pick up a thumping 100 seconds of penalties and finishing dead last.
Eurosport / Fourth-Place Medal