Carl,
Unfortunately, the lookout player's default user is administrator. Thus, you can not restrict the access unless you have the same lookout.sec file in the client machine, what's possible only if you know, and have access to, which machines will connect to your lookout server.
You could set up a mixed security policy. For example, if your clients will always be in your LAN, you can copy lookout.sec file (provided that lookout default autologon as administrator is not set) in every client machine and restrict the access to your process, through IP setting, to those machines only.
Jose.