Imagine delivering a training course to delegates who are half sleep. Is there any point in carrying on? Sure enough, you still get paid for the current session; but surely that’s not your only aim when providing training.
Providing a training course is very much like playing a game. You want to win not just once, but repeatedly. When it comes to winning a particular game (say a board game such as Risk), your aim is not to win only once. Anyone can do that. You could get lucky, you could cheat or you could get away with other people’s mistakes, ignorance or simply lack of interest in the game.
The problem with this mentality is that soon, you will not have any more games to play. People will remember you as the dodgy, cheating player so they will stay away from you or will all gang up against you to make sure that you lose.