Both players unknowingly signed an incorrect scorecard. So please explain to me with your vast knowledge of the game how these situations are different?
Too many clubs, in your bag, for all 18 holes, is not something that is depdendent on a rules review. It is far more cut and dried rule. Having a 15th club can be a huge advantage, though I have no idea if this kid used all 15 or not.
As for the drop, Tiger did get an additional 2 stroke penalty for that. But he was under the impression that the rules committee had okayed his drop interpretation. They ruled differently about the time he finished his round, but had not told him yet when he signed his card. It is not incumbent on players to know that the rules committee have ruled against them.
In fact, the new rule, 33-7, was put in place this year for just this situation, to soften the outdated signing rule under certain circumstances....like THIS one.