I looked at the post-race procedure notes. According to it: “After taking the chequered flag the top three (3) drivers and driver of car 44 (if outside of top tree (3)) should stay on track, drop to the back of the field and then proceed directly to the Grid where there will be the opportunity for post-championship celebrations should they wish to do so.”

Departing drivers weren’t allowed, but the top 3 were allowed to do donuts. They just … didn’t?