HC-05 AT+DISC command

This has arisen from a nearby thread but does not warrant discussion there, and I am concerned that, while being only vaguely interested at the moment, I might be missing something fundamental that I may later regret.

My knowledge of Bluetooth may have some depth but it is not wide at all, and this HC-05 command, AT+DISC, is about as abstruse as you can get. I understand it is all about disconnection, but I have never seen an example of its use. Indeed an example is conspicuously absent from the data sheets, which further makes me wonder if I am missing the bleeding obvious. More to the point, I have always understood that HC-0x has two modes of operation - communications mode, and AT mode - and you cannot be in both modes at the same time, i.e. Bluetooth must be disconnected while sending an AT command.

So what is the sense in sending the AT+DISC command?

I get the impression that this is hardly worth bumping, but the only reference to this command I can find is with the Itead HC-05 shield. This shield uses a slide switch to get into AT mode rather than a momentary button, but I still don't understand what this is about.
I note that it normally takes some serious and studied incompetence to get into AT mode by mistake, but this might not be so much the case when using this shield.
Perhaps an Itead user can enlighten me.....?