That’s hilarious. Even though my 3 units are Entire Places (private apartments) all the units, including mine, share the wifi and so I would know right away if the wifi went off. Surely this is fairly common, it does seem like silly advice.
If you want to check for hidden cameras, you could just wad up a big pile of newspaper in the middle of the room and then stand there with a lighter in your hand, maybe pace around it with a deranged look on your face, waving the lighter around - I bet you’d hear from any host with a hidden camera right away 