It risks creating a self-fulfilling propecy: Statistics show that “Martians” are more likely to be convicted, thus you lower the bar to convict them, which makes them even more likely to be convicted, and so on. In principle you could avoid this by properly conditioning not on Martian conviction rate, but on the rate Martians have been observed doing things which are considered prima facie evidence in a trial. In practice, you would likely end up introducing a bias.
it can be exploited: If, by symmetric Bayesian reasoning, you rise the bar to convict “Earthlings”, you create an incentive for Earthlings to commit crime. Even if most Earthlings are very much law-abiding, few bad Earthlings can benefit a lot from the system and cause lots of damage.
It is intrisically poltically controversial: it runs contrary to the interests of the Martians, and Martians can realistically coordinate to lobby against it, and if their lobbying is unsuccesful, this becomes a point of constant friction between Martians and Earthlings. You don’t want to incite this kind of tension.
Such as?
It risks creating a self-fulfilling propecy: Statistics show that “Martians” are more likely to be convicted, thus you lower the bar to convict them, which makes them even more likely to be convicted, and so on. In principle you could avoid this by properly conditioning not on Martian conviction rate, but on the rate Martians have been observed doing things which are considered prima facie evidence in a trial. In practice, you would likely end up introducing a bias.
it can be exploited: If, by symmetric Bayesian reasoning, you rise the bar to convict “Earthlings”, you create an incentive for Earthlings to commit crime. Even if most Earthlings are very much law-abiding, few bad Earthlings can benefit a lot from the system and cause lots of damage.
It is intrisically poltically controversial: it runs contrary to the interests of the Martians, and Martians can realistically coordinate to lobby against it, and if their lobbying is unsuccesful, this becomes a point of constant friction between Martians and Earthlings. You don’t want to incite this kind of tension.