"I'm sorry sir! I didn't realize you have this un-notarized piece of paper. You can be on your way." Is that how you see it playing out?
Do you really think an agency with a warrant can't figure out who someone is from their handle? "Oh, wow, we will never crack that ODT handle code!"
Why in the hell would I give you my address with all of the gun porn threads? What is the point of meeting at a neutral location if I am going to tell you where my guns are when I am not home?
If I want a gun bad enough, I will sign a generic BOS but I am not telling you where my wife lays her head at night. The question is: Why do you feel the need to compile the personal information of the people on this site?
Do you really believe that someone would go through the trouble of selling a firearm in order to compile someone's name and address? For example, if someone had your phone number they could simply do a reverse search to get your address. ;-)