Very simple...Domino updates the registry to enable itself as a Windows service--when selected during install. Give admins the option to "Add '-jc' to Windows service Registry value" or "Enable Java Controller with service" option.
Otherwise, if admins want to enable the java controller, then they have to remember to ...
When you install Domino on a Windows platform machine, the Domino program directory is not added to the server's path statement.
It would make it alot easier to run nsd.exe, and nserver -c commands (for batch files) if the program directory was already in the path already.