How about an origin agnostic rule for soccer fans: they must wear portable cameras, and pay a bail (which they get back upon good behavior), they pay the escrow

How about an origin agnostic rule for soccer fans: they must wear portable cameras, and pay a bail (which they get back upon good behavior), they pay the escrow at the point of arrival (border train station or at the airport) and return the camera gear at point of departure, upon which they get their escrow back. Aggressive hooligans don't come at all, or pay ever greater escrows (doubling whenever they misbehave, or halvig when they behave (but never halving below the minimum escrow value). I think local population would appreciate such measures, regardless of the origin or religious affiliation of aggressive soccer fans. Sure the soccer industry may suffer from a decrease in ticket sales, but at some point its not soccer industry, but a vacation of violence for the highest bidder... and the local population pays in material damages...