Well it should be obvious for the reasonable people that if this line isn’t drawn the situation is going to be exploited by the unreasonable people. Or by the people who are willing to take advantage of this situation. You understand it of course, but it’s not important to you, just a collateral damage.
2) Even if I make a mistake, I think it's fine to apologize, say I didn't realize (and not repeat it with that person), and move on.
It doesn't have to cripple me into not being able to speak... we're all reasonable people.