In the Mediterranean most of our hunting consists in seizing fish between rocks, crevices and kelp, so I'm afraid that a line clipped to the gun handle would be too much of a hassle.
Miles's system is certainly smart for his kind of hunting, but he's a blue water hunter, while I don't think it would fit for me* in most of my situations. However, I'm quite sure it may work for the deep
aspetto technique (when you wait for fish from a static position) and I'll try it soon as possible, something new can be fun.
*I'm considering to start this new thread for european spearos:
"Chronicles of a brown water hunter".

Anyone want to join in?