I just searched for a friend on Facebook. I found her profile, clicked the Add to Friends button and received this warning.
“Warning! Your account could be disabled. You are using this feature to spam other users. Continued misuse of Facebook’s features will result in your account being disabled if you have any questions or concerns, you can visit our FAQ page.”
Sorry Facebook, I actually do know this person and for a social network to work, you kinda need to be able to add your friends.