I'm just going on this:
Penalties are always unfair, I'd prefer they toss a coin to decide the winner, its about as random.
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Thinking about it, for a penalty taker, there are 5 distinct positions you can put the ball. Tewo bottom corners, two top corners and down the middle. I'm not counting the two heights of down the middle, because essentially if the keeper chooses not to move, he's probably going to save it at either height down the middle.
On the otherhand, a toin coss has only two possible outcomes.
Unfortunately, splitting a goal area into discrete sections isn't entirely realistic because it just doesn't work like that. But regardless, a keeper going top left will most likely not save a ball that goes bottom left, unless he catches it with his foot or something. It's silly to say that penalties (as in the penalty shoot-out system) are random, they're not. There are far too many deterministic factors at play for the idea of randomness to hold water. eg skill, technique, mental strength
Tossing a coin is not like that at all.