I think that it depends upon the age and size of the snake... a baby might be wanting to eat a bit to grow but when it gets older it will most likely refuse food when it is not hungry... at least that is my experience.
Powerfeeding is a method of providing food more often than necessary to force growth. This can be done by offering food multiple times a week, feeding oversized prey or forcing an extra prey item down. The results of doing so have not been scientifically documented, but it is generally accepted that it is an irresponsible practice. "