They've been dealing with this issue for years. If you're on a university campus you can access wikipedia and see the recent changes, there's usually a weird mix of very obscure academic content getting added and undergraduates adding insults about their friends.
If there is a sudden spike in vandalism I believe they just require you to log in with an account usually.
If there is a sudden spike in vandalism I believe they just require you to log in with an account usually.