You must be eighteen years of age or older. ( Well, ‘must’ is a big word -- more like ‘it is recommended for you to’... I'm flexible, but don't you dare report anything you see that strikes you as questionable or suspicious )
You must comment before you add. ( No exceptions this time )
A great deal of linguistic intelligence is required. ( That is, if you want my attention )
You don't have to agree with everything I say and do. ( But by the same token, I don't have to abide by your rules )