I must assume that cisco's application uses the computer as a server or
gateway of some sort.

It may also just be communicating with a router for the information that
is there, however this is a guess.

WiFi radar will show all the wifi connections it sees. This in no
way tells you if they are connected to your router only that they are
there. You could turn off the router and see if any of the connections
turn off as well.

Use the non-broadcasted name setting on your router to keep it from
making it self known and use password security such as WEP to foul would
be road warriors from using your connection.

Set up a gateway like Tork in the repository to make your computer a
gateway so you can keep track of traffic.

You might find a running file on the router I have not tried.

I like the second option myself, but you might like the learning curve.
Tell us what you have decided to use as you mark this thread solved.