I'll second that. I had no idea that option was there. Maybe it's sort of a "parental controls" thing? Otherwise I can't imagine why you would ever want to do that.
Dave -- I'm curious, did you already know about the customize feature, or did you just figure that out right now in response to Michael's question? It's cool either way.
Also, you have some interesting items on the bottom row of your System Preferences. A google search suggests ICS Mac is related to internet sharing. That bottom row is full, I wonder what happens when you add another item! Or what if you added a dozen items?