When a request for a clearance is made (10 minutes+ before the airspace boundary and more if a flight plan is not filed), ATC either issue the clearance or tell the pilot to "remain outside controlled airapace" and pass an expect onward clearance time. That was the system the last time I checked.
In many places outside the UK if you request a routing from a to b to c where b is within controlled airspace, you will either get a clearance or be clearly told to remain outside. a simple roger is not enough.
I find it very common especially round Odiham that when a MATZ transit is requested the atco merely acknowledges the call and must be pressed in order to get the words "MATZ transit approved" - of course when VFR we are usually going throgh anyway but it did make me laugh when 10 minutes after requesting a MATZ transit VFR we told ATC that we had the traffic on final approach 12 O'clock .5nm in sight............lots of eh em eh eh roger!!!
Even better is the MATZ transit approved remain outside the ATZ...........followed by GXXXX confirm remaining outside the ATZ.............followed by GXXXX you were told to remain outside the ATZ you are directly over XYZ airfield.......to which the reply is "GXXXX is 2500ft above XYZ airfield we are overhead and outside the ATZ.
Face it......the system isn't perfect on both the ATC side and the Pilot side.......I wait the time when a pilot chews out an ATCO for something as keeps their licence!
Regards,
DFC