Would that perhaps be a historical thing?
It might, but I tend to think that it's a much bigger problem for ATC with a fastjet or transport pulling up and climbing, as it tends to go a bit quicker than even fast GA type a/c, and that might be some of the reason for the rules.
As for RAF fastjets, well they sure have the airspace incursion drill down cold, and that is in aircraft with proper avionics like the Gr.7 or Jaguar. Not that good at map reading methinks!
