I've been a regular flyer out from Kemble, Blackbushe and White Waltham to CI and the continent. When I first started I was met occasionally and I believe that my pattern of activity is now well understood so I haven't seen anyone for a while.
The last time I was met, it was because there was no GAR. Ops at the airfield had failed to file it for me. The flight plan clearly got someone's attention but the guys who turned up were very polite and once they were sure I knew the score, wasn't taking the mick and just a victim of admin cock up, they toddled off content.
So I agree the system works very well and it behoves us all to play ball and keep vigilant for the bad guys.