I think it is called planning and the application of common sense.
If you are scheduled to operate a night sector then you apply whatever criteria you personally use in order to ensure you are as well rested as you can be prior to the duty. Everybody has their own personal method of achieving this, and it is not a perfect science.
Staying up late the night before often helps. Activity to make you tired and achieve pre flight rest is another. As has already been said the final decision rests with you. If you are not fit to fly then don't. In fact that applies at any time of the day. I have had situations when for one reason or another I have been unable to sleep at night and considered myself unfit for a subsequent day duty and had to phone in. Obviously you are not going to endere yourself to your employer if this is a regular occurance and they have a right to expect you to properly plan your rest periods to make the adjustments.
If you knew you had a subsquent night duty, I cannot understand why you would go to bed at your "normal" time the night before, unless you employed another method for subsequent rest ? At the end of the day the safeguard is you !