Ch-ch-ch-ch-changes...

[Aiwendil]

Davem wrote:

'Do not' is a stronger expression than 'need not'. 'Need not' is too passive

And yet, one cannot alter the fact that Tolkien wrote "need not". I still think it highly improbable that Christopher's accidental omission of the word "need" should precisely coincide with a change that his father was going to make anyway. In all likelihood, he either intended "need not" or felt that there was no significant difference between the two.