Phage

I don't think that the death penalty is always excessive, by the following line of reasoning. Opinions can differ about the maximum penalty for a crime, but a good measure of what the absolute minimum for a crime should be can be found by looking at the infraction itself, e.g. "make the punishment fit the crime". For example suppose shoplifting is punishable by a fine; obviously the fine should never be less than the value of the item shoplifted or it would always be a good idea to steal it even with a 100% chance of being caught. Similarly a fine equal to the value of the item is not enough because there is a chance of getting away with it for free.

In the case of a murder someone has inflicted death and if the punishment must be less than death then it will always be an advantageous trade. Realistically the penalty for a murder should be worse than death, perhaps torture and then execution.

Laws are intended to prevent crimes and so the punishment must be serious enough to make the law effective. A criminal looks at the value they get from committing a crime and compares it with the penalty for the crime less their chance at getting away with it, and judging it worth the risk commits the crime. In this case she apparently judged the profit from the smuggling worth the risk, and now that she is caught she must pay the price.

Admittedly there is no way to assure that innocent people are not convicted of crimes, but this should not affect the severity of punishments. If someone is innocent then the punishment is always excessive; adjusting punishments to be fair to those who are not guilty of the crime would eliminate them completely. Instead effort should be put into improving the system to avoid convicting innocents.