Neighborhood Wheelie Ends with Crash into Parked Car
For starters, motorcycle stunts on the public roads are illegal in most countries and states, and in certain cases, popping a wheelie can result in some jail time, if the offense is repeated, see Illinois.
Assuming the rider couldn't care less for this, it's the danger of property damage, just like we see happening in this very video. And of course, even worse than this - injuring innocent passers-by. It's more than once when bikes whose riders lost control of during wheelies went ahead and injured or even killed pedestrians.
And that's exactly why wheeling on public roads is banned and we support the ban.