So what does the rule mean when it says "or otherwise completely at an opponent’s mercy."? Give me some examples of that besides the ones listed.

Let me point out that i am not talking about an opponent who is in battle or otherwise aware, but one who is clearly flatfooted and distracted. I believe armor is still included.
So it seems to me that a high level target would have up all defenses. They should have walls, armor, alarms, allies, divination, deflection, scent, blindsight, nondetection, etc, going all the time, or quite fighting demons and necroliches and assassins.

Also is a touch attack considered a melee weapon?

ncG1vNJzZmivp6x7prrWqKmlnF6kv6h706GpnpmUqHylscWipaKsmaS7brvFZp%2BepKChsrS%2FjJqlnWWTpMKxecOeZKCqkZiyb3%2BQaXByb18%3D