If a Deco becomes disconnected from the "Main Deco", why is it that it continues to advertise the SSID and allow connections from devices? This creates an island of devices that are unable to connect to the network or the internet.

Wouldn't it be better, and fitting of a mesh network, that if a Deco doesn't have a connection to the "Main Deco" that it stops advertising the SSID so devices can't connect and disconnects devices already connected to it until it re establishes the connection?

The way it is at the moment, if it loses connection it causes all sorts of problems for the devices connected.