It's amazing how some aircraft can fly 99 hours out of 100 without a single defect, but then accumulate 20 defects in that final hour before going in to maintenance. I guess some aircraft are just scared of hangars........
As an engineer pointed out to me, if there is nothing written on the maintenance release they can't justify investigating or rectifying any non-existent faults, and nor can they "discover" things that are only apparent when the aircraft is in flight. They also can't justify the extra man hours chasing defects that are "rumoured" to exist.