CreatePlacemark is called on a 10sec interval, but as you noted, it's not set to refresh on Interval. I believe this occurs because of the FlyToView=1 and refreshVisibility=1 settings.

They are almost certainly using a session, but in my efforts, I couldn't get cookies to work between php and GE. Ultimately I resorted to starting the session and passing the session id to the network links and embedded browser.