I was watching a documentary there the other night on 3e and they came out with this rather startling fact: It takes more Gardai to police the 4,300 crowd at Dalymount Park, than it does for a typical rugby international. I used to live around the ground and remember the heavy atmosphere before games with the huge police presence.
They also showed this clip (along with others) as an illustration of the levels of violence sometimes seen at Irish soccer games.
A quick search of Youtube will yield plenty of results showing LOI supporters causing trouble in and around the grounds of the teams they follow. Are these hooligans (or casuals) now a problem for LOI and Irish soccer in general?