[tor-relays] connections question

I recently had some spare time, so sat looking at the list of connections in arm just for S&G. Most of the connections have fingerprints - but there are always a few "unknown". I run 3 relays on 2 different providers, one of them online over a year, and list my family in torrc. Yet, several "unknowns" with the same IP were on ALL my relays at the same time, many with 2 connections on each. Then there were unknowns with sequential IP addresses - and almost all the unknowns were out of France. Who exactly IS an "UNKNOWN", and why would they be connecting to all my relays in multiples at the same time? Big Brother surveillance?

Daniel