Tax professionals (unlicensed as well as EAs, CPAs, and attorneys) often have to read the actual laws to figure out the correct position to take regarding various tax matters, including numerous court cases, where intepretations of the law are legion. Of course, many of them don't, even when they should, and probably make countless errors which are never caught by the IRS due to lack of 3rd-party information and scarcity of audit resources.
Fortunately, the IRS offers hundreds of publications and form instructions that present about 90% of tax law in layman's terms (i.e. high-school level textbook).
Further, many tax pros offer financial planning, estate planning, and business entity formation/dissolution advice, even when the issues involved are clearly legal and not strictly tax-related.
This then is an example where there are effectively no barriers to entry to practicing law. It seems to work our adquately, errors and all.
[0] I am assuming there are more taxpayers than vehicle drivers, and that tax law is much more complex than vehicle laws, which exist mostly at the state level.
Pedantically, the law indirectly sets the age for purchasing (and not consuming or possessing) alcohol to 21 by punishing states for not having laws against that, and doesn't directly set the age to 21, but it's effectively the same thing.
Another one that comes to mind is KYC/AML laws for financial transactions by the Bank Secrecy Act of 1970. That field in Venmo for "what's this for?" If you write drugs, or crimes, or terrorism, they have to take it seriously. If you move just $3400 of money around 3x in a month, that's considered structuring and is suspicious. Most people don't try and pull out or put in $10k in cash, which would be the biggest interaction with the AML laws, but if you have a bank account (which is only 95.5% of US households), you've interacted with the KYC aspects of the law.
Cannabis is still federally illegal under the Controlled Substances Act of 1970 and a lot of people interact with cannabis on a daily basis. Federal law still influences state behavior, so even in states where it's been legalized for adult use, arguably there's still an interaction with federal law there. Jobs in legalized states can still drug test and fire people for cannabis.
Other substances under the same act that are controlled are also relevant. If someone has ADHD and has a prescription for regulated stimulants, they have to interact with federal law every time they fill their prescription just in case they're secretly Scarface with their 30 pills per month. The number of people with ADHD is far fewer than alcohol drinkers, so this is further down the list, but believable stats on the black market are hard to come by.
Pedantically everywhere except Wisconsin ;) They manage to stay in the good graces of the FedGov while also allowing a parent to take their kid to a bar and buy them a drink.
bitch ass
when I can't delete this message is how long the edit window is. it's total bullshit for dang to add a timeout for editing and not tell the site.