The times for TTA's are known well in advance, yet they still seem to turn up at the same time! There are also plenty of other sites in the area these "aviators" could use, but they insist on using the same valley, the low jets use.
It's been a long time since my hang-gliding days, but good flying sites are precious, and the sites that can be used on a given day are very much dependent on wind direction and speed - to the extent that asking people to put in NOTAMS the day before seems unrealistic. That said, we used to have a Tornado pilot in the hang-gliding club. Seems he found that gliding scratched an itch that bombing about at 500mph didn't.