The 'system' might think that it can restrict the activities of an individual in his/her/its spare time, but I think that this would certainly be viewed as an unreasonable infringement of the rights of the individual in this day and age. It's the same sort of nonsense which, a few years ago, wouldn't allow holding aircrew waiting months for a Hunter TWU to fly Chipmunks to keep current as that would 'slow them down'!
If U/T naval RW pilots are so prone to skill fade, best that they don't drive cars, ride bikes or wet shave either by that stupid generalisation!!