Ah. I think I see the problem here. Allan's translating the French word
defaut as "default," whereas really a better English translation would be "defect."
Knowing that, I can gather the intention of this mod. Guests (and possibly members too) clicking on the "Who's Online" page see a little jokey warning that says basically, "Shame on you for trying to see what others are doing!" Am I right?
It's a cute idea! You just might want to change the wording in the English version, Allan.

And you should definitely explain the purpose of this mod in your OP.