In every language I know, the expressions for saying someone does not need to do something are often used to say they had better not do it. Suppose I want to tell someone in an e-mail, in Chinese, that they do not need to do something and I really just mean they do not need to. They can if they want. What is a good way to say that without implying they should not do it?
I am concerned specifically with the difference between "don't need to" and plain "don't". I might want to say "You don't need to bring snacks to the party" without anyone thinking I mean "Don't bring snacks to the party."
In that case, I do not want to suggest the person not bring snacks. It is fine if they bring snacks. I would even like that. But they are not required to bring snacks.