Just because some inbred gimp from Stoke has wank fantasies about being a hooligan and he calls it 'under 5's' doesn't mean that people will associate this with hooliganism.
Most people have never heard of 'under 5's' and any hooligan links.
Besides, no self respecting hooligan would be wanting to wave a Belgian flag around, they're foreigners and hooligans don't like foreigners.
On a related note, I have a mate who's known as 'over 12' thanks to a comment he once made, he's not a blue though. Thought I'd share that.