I've hardly ever gotten friend requests on here but a couple times when I did I'm sure they just want me to end up seeing their business or website since I hadn't talked to them before.
We don't track if a friend request comes from someone who truly is your real life friend or not, so there's no way to know the actual percent.
Nah, sometimes people add you because they think you are cool, smart, nice, gangster or whatever.. I've had people adding me because they liked my posts and because we reside in the same country. You can PM them asking why they added you, don't be rude to them though even if you suspect spam.
I would say that most of them are . In general they come from people that want to build a reputation . The more you stand out the more of a chance you have of being "friended" out of the blue .
Simple solution... If you get a request and you don't know who it is, delete the request. They don't get any notification whether it was accepted or rejected anyway, and if theyre spamming them to strangers they probably don't have a clue who they sent em to.
Having been involved in the same threads regularly I wasn't unfamiliar with you... Though accepting it may still be perceived as a display of dubious taste.