My first supersonic excursion was in an F-86 on my third ride. Thought I was being clever so laid the shock wave on a little island near the entrance to Pt Phillip Bay near Melbourne.
Don't think any windows were broken but those on the island, looking after the army ordinance stored there, were somewhat shaken and lodged all sorts of complaints.
Next time the natives were becoming accustomed!
That suggestion that a couple of shock waves cancel out each other around Mach 2.0 has to be buncum.
My shocks at Mach 2.5 + over Texas at around FL 5000 didn't seem to worry anyone below.
A rare experience is to experience one from someone coming the other way.
Will monitor the bangs at Avalon with interest.