When I was at CATC, a long time ago, one of my instructors pointed out that ATCOs often have an uncanny inbuilt knack of sussing out when things aren't quite as they should be. His exact words were.......
"You get a feeling in your water".
Notwithstanding the quantum advances in technology that have occurred since I heard those words, I have this feeling about 'Free Route Airspace'.
I hope that I'm wrong.