Numbers of clients not showing


I am curious to find out how people log into the network when I cannot see the number of clients appearing in inSSIDer.In the “last seen” column I can see the status is “Now” but in the clients column some SSIDs without showing clients. Every day the same happening. If someone can log in without letting people see (I mean not not hidden wifi) then can’t really detect anyone use my network. Hope everyone can share with me.

Thanks n regards,