A really basic point that I try to emphasize here is the importance of strong principles. Principles are what drive good, rational people, who understand the dangers of living with criminals in their midst, to treat each crime with consistency, ethics, and unwavering fairness to the accused.
(Note: Europeans get really upset if you refer to minor traffic violations as crimes. Their governments have convinced them that these little things are something different, and therefore get fewer protections. In the US, the legal system also commonly makes a distinction, but in the English language we commonly do not. In this post, I use the term crime to mean “some behavior that society has decided to outlaw,” because using consistent definitions is an important basis for solid principles.)
Take speeding for example. Yes, driving too fast is dangerous. Yes, this affects others so it makes sense that regulations exist. Overall, I’m fine with the idea of having motor vehicle laws including speed limits, with various caveats. However, things are not so simple. A given speed limit set by the government may or may not be appropriate given the science. People are sometimes wrongly accused of things. People are wrongly accused of murder and people are wrongly accused of speeding. These things happen, and it is the job of the judicial system (and actually the police, in the first place) to minimize the chances of dealing out punishment to an innocent party. If you get a ticket, the judicial system exists (in its origins anyway) for your benefit.
Many people say, “but the system will break down if we allow every person a fair trial.” This is an extremely common response when talking to French people about photocop tickets, and it is an extremely short-sighted view. First, note that taking money from innocent people does nothing to prevent future violations, so the very problem that the law exists to address is completely unaffected. Second, note that gutting protections for the innocent financially benefits the very group of people gutting these protections. Yes, some people that are accused actually did the crime. Some of those crimes are actually a menace to society and I think we can mostly agree that the culprit should be punished. But if the list of infractions in a jurisdiction is so long that the jurisdiction cannot employ enough people to handle the burden on the court system, then not all of those laws are really necessary. The reason an unprosecutable number of traffic tickets are written is that the current laws are catching massive swaths of the population (and many of these people have reasonable defenses). If such a large percentage of drivers is ticketed for speeding, for example, then the current speed laws and enforcement are clearly not serving the will of the people, regardless of effectiveness.
A government simply should not be able to force a citizen to part with freedom or property without providing ample evidence that a crime occurred and that the accused is, in fact, the culprit. This is what it means to have principles. Most current governments (certainly that of France or most US jurisdictions) are not principled. Some of the actors in these systems naively believe that photo-enforcement, for example, is 100% correct. That’s cute (also wildly wrong), and individuals may think they are acting in a principled manner, but the system itself is really not interested in working for the people.