Imagine that in polish league, currently second division, but probably first soon, there is a club which fans cant travel to any away game, because the hosting clubs ban away fans entrance with out any real reasoning, just saying its dangerous for them (even though police disagrees). It all happens because this particular club fans didnt sign some ultras pact (regarding the use of machetes lol) and the away team ultras force their team (yes they do have such powers lol) to ban away fans arrive.
Those club just pay like 5000 euro penalty for nit letting the fans.