This is mentioned in the article when discussing a player that found the optimum route:
> Sarah also did something that appeared a bit unnatural. Instead of simply continuing straight a few times, she intuitively and preemptively turned in a snake-like pattern. This highlighted a key difference between real-life mowing and our simplified game, an approach that strong mowers exploited. Sarah, an avid gamer, seemed to recognize this strategy immediately.
> Sarah, an avid gamer, seemed to recognize this strategy immediately.
I have also played a lot of ChuChu Rocket!
The thing is, one needs to consider more than efficiency, but the overall health and appearance of the lawn --- as noted on _Magnum PI_, it is necessary to vary the cutting so that the lawn does not develop a "grain" where it lays unevenly.