Wheelies on racetracks - particularly at Shannonville - have been frowned upon for a long, long time, and it goes back to an incident that the younger folks would not know of. The possibility of oil spillage from an unnecessary crash is one thing, but there is more to it.
Years back, a racer named Glenn Schaubel (I may have the spelling wrong) did a wheelie across the finish line to take the checkered flag. He went over backwards, came off the bike, and the rider behind did not have time to take evasive action, and hit him. This was a fatal crash, and it happened right in front of a lot of us who are now old-timers, myself included.
Ever since then, "power wheelies" that come from exiting a corner have been tolerated, but any sort of deliberate wheelie, or failing to set down a power wheelie in any sort of reasonable time, is frowned upon and most reputable track-day providers will black-flag anyone doing it.
The racetrack is for riding fast, not for doing stunts. Wheelies and the like fall into the category of "unpredictable riding", and it opens up the same sort of discussions that we have had about people screwing around on the straightaway at Mosport because they were trying to position themselves to be in view of another rider's on-board camera so that they could film themselves.
The prime directive when riding on a racetrack is to ride in a manner that other riders can predict. That means being on the correct line in corners (or as close as you can make it), and accelerating out of corners, and going fast in a straight line on straightaways straight towards your next turn-in point (no weaving, no changing your mind about your entrance point at the last moment - failure of people to do the latter is why I have mostly stopped doing track days), and braking at some semblance of the correct braking point, and being consistent lap after lap after lap. The faster you go, and the closer you are to riding with other riders doing the same thing, the more critical this is.
