AIS not an anti-Collision System

My ship was entering a port which use an own portable computer navigation system based on DGPS and AIS info that keeps them in the middle of the channels and can predict the ETA of opposing traffic. They either use an own antenna that they set up in the centre line of the ship, or plug in to our ais connection. In this case the latter.

While sailing into port, the pilot saw on his system that another ship was still at the berth, although a security call, passing a certain point, had been made. He called his colleague on the VHF only to find out that the ship was indeed underway. Double checking the computer he saw that the ship/AIS was still docked. Confusion galore, negative things were said about our AIS connection, AIS in general, etc etc. On my assurance that my ships systems worked, we contacted the other ship again. There the pilot got the captain up on the bridge (who for some incomprehensible reason was sitting in his cabin) and this captain advised that he had left his AIS system behind in the drydock that he was coming from for repairs. Obviously the shipyard had set up the AIS on a test bench and was happily transmitting away. Not dangerous, but very peculiar to see, with a ship on the way and the AIS locator staying behind.

While sailing further into the same port, we came closer to the dock and saw a bulker docked at the dock. However his AIS was three (!!) cables to the south of him, right at the municipal airport. The pilot passed a message on about this so hopefully they corrected the settings, before they sailed. When docked, such an anomaly is not an issue, however an AIS 3 cables off when approaching a pilot station or VTSS cross roads could cause issues. It gave me the chance to teach the navigators a valuable lesson, NOT to use AIS for anti collision, but what it is meant for, an information system.