Yes, it can.  What the mod was reference is the use of VPNs.  Even so, a person who uses VPNs telegraphs the fact because their log ons are always using a different IP.   It's not proof of a sock, but it also does not disprove it's a sock.  It's an unknown. 
Example;  my IP is pretty constant since I post from home on my laptop.  It changed a couple weeks ago when I switched internet servers, but was consistent before and remains consistent after. If I had a secondary account, it would show up as the same IP.    A person who uses a VPN is constantly changing.  Harder to prove if they have socks, but it leaves the door open.
IT/techie people are free to chime in with their thoughts.