You make a valid point - However if the word is unknown to you could you find it offensive? I am not sure what people would think of this.

I think that dws's suggestion about a proxy here at Re: Profanity in the monastery would suite best and one would have to manage a list of words they found offensive in their own proxy.

Update: Not every newbie has the ability to find and customise a proxy written in perl to perform this filtering for them.. hence the idea which in retrospect is probably not feasible to maintain centerally any way.