At least in Brazil you can't enforce something the law doesn't allow in a contract - that clause would be considered void without nullifying the contract. And Labour law in Brazil leans (or used to lean) more in favor of the employee,so yes, the law would win. Another aspect there is that unions are more common than in the US, and they will help in such cases.
Unless the law also has severe penalty for including such terms, of course they are. They don't need to dissuade 100% of people from breaking 100% of the terms to be of use to the company.
"Under the terms of NDAs I have signed I am not free to disclose that list."
Similar to asking the candidate what they dislike about their previous boss. Their response may indicate how they’ll talk about you someday.