One of the most interesting things Scott Alexander got from Legal Systems Very Different From Ours is that all legal systems need a punishment of last resort — one that can be enforced whether or not the offender agrees with it — but these punishments practically never happen in real life:
The Gypsies and Amish will ostracize members who defy the court — but since everyone lives in fear of ostracization, in real life they’ll just pay the fine or make their public confession or whatever. The English will hang criminals at the drop of a hat — but since the threat of hanging incentivizes them to bribe prosecutors, in reality few people will need to be hanged. The Icelandic courts could declare offenders outlaws who can be killed without repercussion — but the threat encourages Icelanders to pay the wergeld, and nobody has to get outlawed. The Somalis are ready to have murderous family feuds — but the possibility of such a feud keeps people willing to go to arbitration. Even our own legal system works like this. The police can physically drag you to jail, kicking and screaming. But more likely you’re going to plea bargain, or agree to community service, or at least be cooperative and polite while the police take you away. Plea bargains — which are easier for prosecutors, easier for defendants, and easier for taxpayers — seem like a good example of cultural evolution in action; once someone thought them up, there was no way they weren’t going to take over everything despite their very serious costs.
Plea bargains facilitate policing for profit. Plea bargains are not better for everybody. Plea bargains are better for the people who can coerce others to obey or suffer pain.