They probably aren't using location but IP block. In fact, I'm almost certain your IP block is used for both suggested friends and your Newsfeed.

I used to see my coworkers all the time in my Newsfeed, but now that I don't work there (and therefore we don't share an IP anymore) I suddenly started seeing them a lot less.

I go to their page and see they are posting, and after interacting with a few posts they started showing up again, but I have to go to their page and interact every few weeks to get them to keep showing up.

Also, whenever I go and visit the old office, if I use Facebook there, all of a sudden I get them all showing up in my Newsfeed again.