In a recent article in a regional Australian newspaper, an expat Japanese sushi chef complained that sushi chefs Down Under were getting a bit carried away with the mayo, not to mention the avocado, claiming that overuse of these two non-Japanese ingredients spoiled the sushi-eating experience. He added that in Japan, they don't use as much.
Obviously, he hasn't been to a kaiten-zushi restaurant in his native country lately. Kaiten sushi are the fast-food dispensers of Japan's most distinctive cuisine, where sushi is churned out by human and/or automated means and placed on conveyor belts that pass in front of patrons who just pick them up. After they're finished, an employee counts the dishes and adds up the bill. The incorporation of mass-production methods means kaiten-zushi establishments can cater to families with young children, a demographic that traditionally was not welcome at sushi bars, where the dynamic is more personal: You deal directly with a chef who stands in front of you and makes dishes to your order. As kaiten chains became more widespread and more cost efficient, the variety of dishes expanded to satisfy newer or younger tastes; which is why what they now serve will likely offend the finer sensibilities, not to mention the pride, of traditional sushi chefs. Not only are mayonnaise and avocado regular ingredients at kaiten chains (and, contrary to what the gentleman in Cairns claims, slathered on quite liberally), but they also offer salads, Western-style desserts, and, making the fast-food analogy complete, hamburger and hot dog sushi.