Using loopholes to your advantage isn't cheating. It's legal. If a taxpayer can carry forward losses in order to not pay taxes, then the taxpayer is legally taking advantage of the rules to his or her benefit. It would be crazy to do otherwise.

If a parent decides to holdback a child to take advantage of the academic, social and athletic benefits that comes with a holdback (or a PG year), it is simply taking advantage of rules (or financial wherewithal) to the benefit of the child.