Catania or death?

Catania fans have been banned from attending their club's match at Inter Milan this weekend. I don't quite understand how that works - do the security guards ask each fan who they're rooting for as they enter the stadium? I would think this is an easy situation for Catania fans to get around:

Guard: Catania or Inter?
Catania Fan: Inter.
Guard: OK, you can get through.

See, I just did it! For further help, I'll let my friend Eddie demonstrate:



With this guide, any Catania fan should be able to cause further havoc and destruction. Good luck!