It could actually be correct. Anyone who doesn't live in a city centre is likely to know someone in their village or town who owns a shotgun for either sport or pest control.
Also, it doesn't take into account those who honestly believe that the class nutter's dad owns the gun he's infamous for, even if they've never seen it themselves. (When I was at school the class nutter's dad reputedly had an M16. I don't know how true that was but he did actually bring a grenade to school once.. but then I never *actually* saw it.