I always think that training is a good reminder, and I don't think that training, when it comes to procurement, should be a one and done. I think that it should be repeated after a certain period of time, because the rules do change or because maybe you haven't done procurement in a long time and it's a good reminder.
However, that's just one step; that's not going to cure it all. You do have to have someone who monitors, and every procurement group within a department should have its own monitoring to see internally whether or not rules are being applied. When they're not, that's when you highlight areas of, perhaps, repeat training or individuals who just need some coaching.
Training is just the beginning of what is needed to make sure that procurement is properly done.