Tunneling through a VPS=PVA?

I tried SSH tunneling through both my VPS at www.linode.com and an Amazon EC2 Instance and both of them required PVA's when I got to CL. Do you think CL just softblocked the whole range of IPs for both of these providers? I think its kinda unlikely that someone was doing the exact same thing as me from the same machine. Or is there a way that CL is "seeing through" my tunneling?