Taken from the first link:
It has three methods of simplifying the connection of wireless devices to WPA2 protected access points:
Push Button Connect (PBC) requires the user to push a button on the router which allows it to communicate with a client needing configuration. The client attempts to connect and the router simply sends it the security configuration required to communicate.
Client PIN mode is where the client device supports WPS and has a PIN assigned by the manufacturer. You then login to the router's management interface and enter the PIN to authorize that client to obtain the encryption configuration.
Router PIN mode allows a client to connect by entering a secret PIN from a label on the router, or from its management interface which authorizes the client to obtain the security configuration details.
The first method requires physical access, while the second requires administrative access, both of these pass muster. The third however, can be accomplished only through the use of the Wi-Fi radio.
So no you don't need to have physical access to the router.