Warning in visitor messaging

[bashy]

Hi folks

I just done a search for this but cannot find it..
I also done a search for how to make a plugin/product, again didnt find out

Anyway, i keep getting messages in my profile for help on the forum and such like
At present i am just ignoring them....

So heres the request:

In the visitors message box where they leave you a profile message, is it possible
to add a warning message in box where they type the message and as soon as they
click in the box to start typing the warning disappears?

or perhaps a warning box popup/redirect screen that warns them and they must agree that its not a request for help and if it is they will get a ban.....

Something along those lines,

Is this at all possible please?