are Linked-In and Facebook allowed by law to send friend request without your knowledge?

[David]

friend request have been accepted by people whom i did not want to be friends with.
i do not know when or how the friend requests were made or sent
the websites do not respond to my inquiries when i ask "who sent the friend requests?"
does anyone know how to contact their management staffs?
when i ask people i know if they sent me a friend request, they too said no
why do these companies send friend requests that were never requested for by anybody?

[Ronnie]

if you use friend finder in Facebook then it will send request to mutual friends automatically