Yes I do make the occasional electronics post..
Fortuitous means
1: Occurring by chance According toI can get an open ground occurring by chance? Lucky me. The TDA7560 has 6 out of 25 pins that make ground connections and one via cap. I wonder which grounds can be fortuitous. :P
I'm guessing the fortuitous open gnd protection refers to if the signal ground gets cut, the amp or speakers don't blow.