While this does look like a very squidly thing to do, I am pretty sure that this happened at a WSB race last year. I may have the nevue wrong, but I know it was a high-level professional race. I saw that race (not live, but as a re-run) last year on Speed. I think it was more a teasing way to look behind him. The rider was trying to make the rider behind him jealous, and ended up taking himself out. Don't quote me on any of this except for the fact that this was not some squid race.
James Stewart did a 'watch ya call it' at the finish of last weeks motocross race. His picture with the bike crossed-up made a good full page ad for Kawasaki in the following issue of Cycle News. At least some of these finish line stunts aren't all foolishness.