I recall some discussion with my stepmother back in the 1990’s where there was some news item about prostitution - she wondered how that even worked? I told her the news article mentioned personal ads, looked at the day’s edition of The Globe and Mail which was/is Canada’s staid business newspaper. The ad we found funny, sticks in my mind, was some lady advertising services for “…boy scout who knows the ropes…”
I did collect some “tart cards” when I was in England in 1991 - very clever things, stuck into every nook and cranny downtown, especially those red phone booths. “For a spanking good time call…” I was especially amazed to find these sort of cards offering massages stuck around our hotel in Dubai a few years ago, of all places. I guess that happens everywhere.
The thing with bosses who refuse to pay overtime, is that in the civilized world, and also in some US states, there is a thing called the Labor Standards Board, and employers who cheat on overtime can be charged and fined and made to pay overtime. The trick is to wait until some is owing, quit, and try to collect. Generally, the employer will find that too many such complaints can have negative ramifications - very different than a worker being threatened physically, or with deportation. A construction boss may hire undocumented workers because the same threat of deportation can be used against them if they ask for their legitimate pay.
As for constitutionality - you can vote, you can give someone money, you can’t pay someone to vote for you. You can copy a book or movie, people can give you money, but you can’t sell a copy of a book or movie you don’t own copyright to. (You cannot even give it away). You can give people rides, they can hand you money, but you cannot make a business of it unless you have a taxi license. You can have a child you can’t care for and give it freely to someone who will take care of them for you, but they cannot buy the child off you. A lot of things become illegal when money changes hands to facilitate it.
the general theory of the constitution is that what is not enumerated as a power of government is a right reserved for the citizen. yet, for example, there is nothing in the constitution that explicitly gives the government, for example, the right to prohibit theft or fraud, or even murder. IANAL, but there is some legal theory (plus common law) I’m guessing that allows the states to prohibit certain activities in the pursuit of peace, order, and good government?