Bugoutwest is right to be concerned about CAT flying outside CAS, in a busy part of the country, at levels used by light aircraft (including gliders). If CAS is available it should be used. Flying over a busy gliding site or aerodrome at these sort of altitudes and speeds, in an unmanoeverable jet is pretty poor airmanship. Airline pilots will not be keeping a good lookout and they are unlikely to be supplied with a deconfliction service (particularly in an area of high traffic density). Gliders do not always show on primary radar and when they do, are often mistaken as clutter or simply ignored by ATCOs. Some of the comments in reply to Bugout (while probably technically correct) show naivety and a lack of appreciation.