Yep, it does jack. It does limit your debug options, if youre into that sort of thing. This is just a way over the top fix, to disable updating.
Just keep your regular ReBug, and unplug or turn off the lan. Or tell people to just not mess with your ps3.
If you had to change a tire on your car, would you take off the fender? If your an idiot i guess.
This is just about the most messed thing you could do to downloaders. Give them a "hint hint" so they think it is worth the time it takes to download. Why not give them a piece of toilet paper, and say, here's a special napkin, hint hint.
People would do better spending their time, picking their nose, or staring at the wall.