My last two thoughts on the subject:
1. I reject the notion that you have to throw games to train out of position, and seeing as how I did it, my opinion is pretty resolute.
2. If you can train all three players in one game, it takes away the concept of having to make some compromises; it makes it possible to be your most competitive and still train three unique players with no side effects (other than perhaps bailing out of the Cup early or throwing a league game). The difference is now the teams that already throw games like that will now also be able to get a full week's training to do so. It replaces a meaningful decision (to do training or squeeze a little more productivity out of the roster) with an almost mandatory decision to do both.