First the software will know they are familiar
on the other hand the advantage is probably if they are nottrusted you may not use file sharing trough Win network.The password is only as a confirmation on the other site that you are aware of the device and youaccept access to your network.
I think there is nothing else to discuss on what are advantages of using passwords to protecet any network
If you still need any clarifications please go ahead
McAfee's "My Home Network" as the other computers listed as "untrusted". I was just wondering what the difference is. Thanks for the reply.