This one’s extremly easy to reproduce. Work on a Vista 64bit platform. Take any .exe in task manager that was launched as a service from the services.msc list. Let us start with a very simple example. The Print Spooler Service which is active by default launches spoolsv.exe. Attempt and create D+ rules that prevent process termination for it. Then end it with task manager. You will be able to. This works for everything that was started as a system service.
This is reminiscent of my previous thread, where I had neither stated nor understood what was going on properly. Now I do and it seems to be a general issue.