I don't really see why not.  For the name searcher issue, if you can't find the name, you know that the person who owns it doesn't want it to be found.  So just leave it alone.  At the very least, hide the username in the ACS so nobody bothers them about it.

And notes in big letters don't stop anyone.  When you tell someone not to do something, they're just going to want to do it more.  Everyone should know that by now.  And what about the users who don't speak much English?  They may not understand exactly what you're saying.

I don't own any expensive pets.  My best one is my own username...I doubt anyone's ever going to offer on that.  So I see this objectively, and I say, there really is no problem with it.  I can see how having to drop everything to view an alert and read another "Can I have this pet?" rmail is annoying.

Just saying.