There are apps that let you detect what has been installed on computers in your network. Forgot what they called them
They are client server applications, right? Let me know an example of them plz.

I think if I install without MSDE it won't send any signal probably.
I think MSDE installs itself as a service, so network admins can easily connect to your computer via computer management and detect it even if it doesnt send any signal. And for the whole program (VS.NET), if they can connect to your registry (I know they can but not sure about the hives they can see) they maybe able to detect that too.