There's an anecdote near the start of a popular economics textbook that attempts to illustrate the importance of incentives and how innocent legislation can go awry. The story is that laws mandating seatbelt use actually increase the number of car accidents and fatalities, because once drivers start wearing seatbelts they'll feel safer to drive more recklessly and will thus cause more accidents, offsetting the safety benefit of seatbelts and increasing the likelihood of getting pedestrians killed as a result.
Now, this is just an explanatory story from the start of an Econ 101 textbook and obviously not super important for the field or anything, but I've heard a lot of libertarian and general right-wing types cite it as proof that government intervention is always bad etc. But I was thinking about it in the shower recently and like, the story straight-up does not make sense and I'm pretty sure the supposed empirical results it's trying to explain are wrong.
Think about it. If a driver wasn't using seatbelts before the law was implemented, he either didn't believe in the safety benefits of seatbelts or thought it was worth the greater risk of not wearing it for the sake of convenience or whatever. Now, passing a law obviously doesn't significantly change people's beliefs around seatbelt safety, it just adds "you might get fined" to the existing risk of "you might get injured/killed" to the calculations of people who already believe seatbelts increase safety. So the law would only change the behavior of people who:
>already think seatbelts make them less likely to get injured or killed
>still refuse to wear them because they don't care that much
>but will wear them if there's a law, because they do care about getting fined (more than they care about getting injured or killed)
>will then decide that it's worth driving more recklessly because "hey, I'm already wearing a seatbelt anyway", despite having no previous inclination to do so (remember, the option to do this was always available to them)
Intuitively, this odd set of specific beliefs just doesn't seem like it applies to enough people to offset the benefits of the law, and indeed, a quick search has only turned up results that support the "naive" notion that seatbelt laws reduce fatalities. People just treat the "refutation" like it must be true without verifying it themselves.
All of which is to say: kids, if a strange economist starts talking to you about perverse incentives and revealed preference, go inside and tell an adult.