> if the edge case is possible, it will happen

By that argument, you will:

* beat your wife

* murder an enemy

* shoot up a school full of children

* commit arson

* jump bail

* evade arrest

* die in a hail of bullets

So, assuming all those eventualities, why shouldn't we just put you to death now?

To spare you the rhetorical exercise, the answer is because we don't punish you for the things you might do, but only punish you for a) the things that you have done, b) that we can prove, c) beyond a reasonable doubt, d) in a court of law, e) before a jury of your peers.