A few years ago, I came face to face with a large retractable helicopter in the competition box at the UK Nationals. I was so close that I can still recall the number of pens that the chap in the RHS had in his breast pocket. Yet, he still hadn't seen me. I've had gliders run through the box (Fenland) and I've seen a gaggle of microlights landing non-radio whilst the comp was in progress in the overhead.
People make mistakes, we all know that they should not - accept it.
Narrow Route Brief, and a couple of phone calls for PPR have kept me out of trouble over the last 15 years.
Notams are a little clunky but they are the best that we have today. Live with it until something better comes along or you decide to create something better. Frankly they work ok for me.
Stik