I echo the sentiments about good sportsmanship, honesty, and trust. We are, and always will be, an honor system game. No matter how vigilant we are, it will always be easy for people to cheat or...make advantageous retroactive decisions (“Gosh, I was definitely only holding cheap poisons in my hand when you disarmed me, not the good stuff that I’m pulling out now!”).
If you’re worried about the ability to enforce a rule, it means you’re not willing to assume your fellow players are playing honestly, and that’s the wrong approach.