French language Q&A Forum

I am confused by some of the answers to quiz questions in this lesson. For me, the construction "Il faut ..." translates well into "One must ..." in English. While we don't use "One must ..." much in modern English, it indicates that we're talking about a general proposition: It means I / you / he / she / we / they must. But some of the quiz answers here seem to say that "Il faut ..." indicates something less than a requirement that should apply to everyone, barring any qualification that might be given in the text, and barring any clarification that might be given by the context. "Il ne faut pas marcher sur la pelouse," for example, means something like "It's forbidden to walk on the grass," or "No one should walk on the grass," not just "You mustn't walk on the grass," doesn't it? What am I missing?

In Latin and English a future active indicative sometimes acts as an imperative command, like "Thou shalt not steal." I'm curious if there is any parallel to this in French? Thank you!

I have trouble hearing the difference between "serai" and "serais".  Does one rely on context, or is there some magic formula that will make everything clear? :)