Those are not "traps" - although I understand what Ayoob was getting at. He is trying real hard not to say that the folks he used as examples constructed their own traps and then walked right into them.
"Know the law" is always good advice. One of the better things about OCDO is that there are enough lawyers* here who will first cite what they think is the relevant ststute and associated case law, and then explain what they think it means in practical terms. Then eer have the next set of lawyers* who will explain why they think the first set were wrong and what they think is the real correct least not-wrong answer.
Even when you pay an attorney* for legal advice, the last words you will hear from a good one are "But you need to decide for yourself what to do."
* A "lawyer" is a person who know the law, as opposed to an "attorney" who is a member of the guild and can accept money or other valuables for their thoughts. Some "attorneys" are even allowed to stand in front of a judge and argue about who's interpretation of the law is least not-wrong. (Think of the British sysytem of "solicitors" who do all the mundane scut work and "counsellors" who dress up in wigs and robes and go argue with judges.)
This does not by any stretch mean that, for example, just because I know a whole lot about wills I can, as long as I do not take valuables in exchange for doing it, I can legally draw up a will for someone else. Nope! Not allowed to, and even if I did a perfect job it might be invalidated just because of who drew it up. OTOH, I can draw up my own will and even if I miss a few of the finer points it will stand up. (Juast one more eample og "knowing the law".)