For some VPNs that I need to connect to, the required program is called Check Point Endpoint Security. One of the most annoying features of the application is that it starts up when your computer starts, and throws up the connect dialog immediately.
There is no way in the UI to disable the autostart. What you have to do is to go into the file
and change the part where it says
Alternatively you can use the plist editor from Xcode and change the RunAtLoad setting from YES to NO.
One major itch scratched. Thanks to my colleague SimonD for finding the solution.