Yeah, but only around the time of sports matches. That makes it predictable, and the anti-hooligan magic can be more effeciently focused. It's actually a little-known fact that Quidditch matches are timed with the solstice so that the anti-hooligan wards are at their strongest.

The Irish are much more unpredictable with their drunken hooliganism, so in the early days they used to break through the wards by accident and go on drunken rampages across Wales before eventually being segregated to their own, smaller island.