I get this too sometimes (get friend requests from people not in my location) I think its because there is a feature in everyone's profile that says...

others like you...

you find that by clicking the tab my profile at the top of the page. then scrolling down the list on the left side.

by clicking on ....others like you... you can see a list of users that have something in common with what you have for your own profile information..

this way members can become friends with those that have something in common with them regardless of location.

you do have the option of not accepting someones friend request and also unfriending someone you dont want to have on your friends list.

when someone sends me a friend request I check out their profile and posts to decide if I want to add them. if they have nothing it usually means they just registered and are looking for others like them. I accept those requests but dont always keep those on my friends listings depending upon what their future posts and profile end up being, if they constantly post things that are triggering to me thats a red flag for removing them from my friends list.