I sent Ahuviyaa friend request because she liked my comments. She had a follow button (and you could comment on her public comments) in addition to a friend button and message button.
If someone on Facebook has a follow button as well as a friend button and you can comment on that person's public comments and that person likes what you post, chances are you can send that person a friend request and it will be accepted.
She later blocked me over an argument about an electric stun collar she had on Facebook with another friend.
Sarah (Pixyteri) was already following me on Twitter. I asked her if she wanted to be friends on Facebook and she accepted.
I have never been on Jay Geis' (Golden Knight) friend list. I have never sent Nick Stoutzenberger (Sick Nick) a friend request. While I would never write on Deviant Art what Jay Geis wrote, there is a difference. In the case of Jay Geis it was a story, in the case of Sick Nick it was for real.
In the case of Leonard Shaner, he sent me a friend request and I declined because he was too controversial.
As a suggestion, I think you should have a policy that only people who are actively on sex offender registry that is accessible to the general public should be labeled with terms such as "sex offender" or "pedophile". For good measure you should include a link to his/her profile on the registry. I will put more later on today.