I was mostly making the point that there are legitimate reasons occasionally to ban certain game aspects in a competitive setting. I wasn't trying to say there was a legitimate case for it with Halo, and just from the sounds of it with banning a shotgun I doubted there was. There are very rarely times where banning anything is necessary to give a competitive game variety, or avoid random chance winning over actual skill.
For what it's worth, I feel the same way about people who play competitive TF2 (even though I don't) and require a certain class makeup on each team, or ban the Sandman baseball bat for scout. If some team makeups are better than others then it'll all come out naturally anyway and people will use what works for their team. And if someone doesn't like getting stunned by a baseball that hits them in the head I suggest they learn to dodge better.
Most things done in the name of keeping a game skill based are a load of crap. But anyway, I think we're probably a little off topic now so I'll leave it at that.