Neither are unethical, as neither are misrepresentations or dishonest.
There's no reason you cannot agree to terms that are unenforceable. People do it all the time. You do, too. The cost of breaking your word is not legal action, but the other party will consider you dishonorable.
> Both of the aforementioned points are made worse by the fact that the companies generally have more leverage + more ability to retain legal counsel, make it a lot worse, because that means that they most certainly knowingly do this.
If you're negotiating for a 6 figure job, you can afford $400 to have a lawyer review your contract. Keep in mind that the fact that you are offered more than minimum wage means you do have leverage.
Even if you can't afford a lawyer, you can ask on HN :-) or at least google the clauses.