I thought I replied to this. Guess I didn't.
I can't see how pulling the output off the amp would hurt it - if it is what I THINK it is, class B Push-Pull, then taking a load away is not going to hurt it. Of course, loading it to heavily (too low of an impedance) could be harmful, but not "under-loading" it.
And as for Class D, I'm not sure I believe removing a load would be harmful in the single-ended configuration. As to the 'full bridge' design, I'm still not sure it would be harmful, but I am less certain.
On a related note - does anyone know what is going on with FOUR wires to each rear speaker? The designations on the diagram don't add up for me.
OOOPS... as for pulling the inputs, I am sure this is not harmful. HOWEVER, when you do that, you run the head with no load - and isn't that supposed to be bad, by your own thinking??
(Seriously, just insulate the disconnected wires and you'll be fine).