too many pilots automatically think of CAS as an absolute no-go zone and a re-education programme would be needed.
While no CAS (except the obvious) should be seen as a no go area by pilots, it is often a problem caused by the controlling ATS wherein they will deny transits the majority of the time. If pilot A trundles up to Airspace Z and gets denied a transit time after time again, sooner or later he will stop asking or ask a lot less frequently, and will most likely mention to other pilots that it is difficult to get into so they are less likely to try and then they tell people the same.