Alex - You make a good point, re 'children aged 16-17 who could be playing in 'adult' (open age) football... However we were told at Surrey FA course that only referees who were intending to referee youth football needed to be CRC checked...
Q. Do I need a CRC to register as a referee?
A. At present only referees who are over the age of 16 (on the date of registration) and who intend to officiate in youth football (i.e. under 18) need to have an FA accepted CRC. In the event that you do not possess an FA approved CRC and you indicate during the registration process that it is your intention to officiate in youth football during season 2014/15, you will still be able to complete your referee registration but will need to have an FA accepted CRC in place by September 1st 2014.