Not the PADI course, but when I was in the Military, myself and 3 lads from my workplace had to go on a First Aid Refresher, you know the type of course you think Oh God, its going to be so boring, I know it all, I'll just fall asleep (Please bear in mind I was very young at the time!!) Anyway as it turned out, I didnt know it all (neither did the rest of the course and it was very interesting.... bout a week later, the other 3guys saw a car crash right in front of them, pulled 3 people out of a car wreck no fatalities, big press coverage, military boys came good
Speaking to them later, they all agreed if they hadnt been on the course their actions may have been not so quick and right......
So doing a course is great, doing a refesher is even better