Not an exploit, just clever use of nameplates (and the chat bubble frames as well at some point)
https://www.youtube.com/watch?v=jGMDYqHokoA
https://www.youtube.com/watch?v=QnCvyRb4t0Y
Notice the colored circles and lines over players connecting to nameplates. It was during that patch friendly nameplates were completely locked down.