>it announces a huge number of APs with random names, making it hard for devices to connect to real networks

How does that even work? I get it will prevent someone from choosing the right network to join, but I can't imagine how it prevents connection if the network is already remembered (ie. autoconnect)

It jams the announcement channels, and lots of devices only show the X strongest networks so the autoconnecters which get their listing after said filter don't see the real network at all as a candidate when the jammer is sending strong enough.