Let's forget Alvarez.
This Palermo goal (who else for bizarre stuff, for the good and bad).
It's pretty clear that he touched two times. Its pretty clear that he had no intention to do such thing.
As a side note, the goal was allowed and it was sent to FIFA later, after refs from AFA protested (the rival team didn't say a thing when happened, in those days it was more usual to think "this fvcker luck") and FIFA allowed it because they saw no intention of taking an advantage.
In my view? it should have been disallowed, yet be retaken. He had no intention to take advantage, yet the double touch existed. It doesn't matter if it was gross, there was no intention.
It will be more in line with what happens when the keeper (in most cases) intentionally crosses the line to gain an advantage and saves it. Some people will say, within reason, that in this cases is retaken because there was NO goal, so we can't create a goal out of nothing, it would be too much. Yet at the same time, to retake the penalty, with all the nerves involved, because the keeper deliberated seek an unfair adavantge isn't fair either.
So in both cases, when the keeper saves it crossing the line or when the goal happens with an unintentional double touch, it should be retake.
In fact this is one of the few instances, rules, that is way easier to detect intention and sthg like that can be apply.
There is even more space to complains in unintentional hands that many times are not called (like happened in this last match between Real and Aleti with Giuliano's one), than in this penalty situations. So there is no harm to review the rule and not just fall in the "rules are rules", or black and white decisions that go against the spirit of the rule itself. It's as simple as that.
Back to Alvarez, of course in this case, given the instance, the rivalry, the exposure would explode and have tons of reactions, from conspiracies to 4545 cameras, opions and such, but won't be bad to actually do sthg better with the rule after this situation.