If the aim is to avoid multiple redirections, the rule would have to be - leave it alone unless you know the final ID.
And an LNAB change is a merge - it does what you're otherwise told to avoid, it creates a duplicate.
Whether Style Guide trumps redirections, I don't think we know. A lot of LNAB changes do get done for stylistic reasons only.
With Unknowns it's particularly difficult to establish that there isn't a duplicate out there.
And then again, the Unknown might be discovered, but that risk is unavoidable. You can't not create an Unknown on the grounds that it might be found.
Or can you? If you fill in a guess, you might get lucky and then you've saved a redirection.
And of course there's always a "source" out there that fills in any blank with a guess, a rumour, a mistake, or a bit of wishful thinking. Depends how you like to do your genealogy. WikiTree hasn't decided what sort of genealogist it wants to be.
You could get a situation where somebody creates an Unknown, somebody else finds a name and thinks they've solved the problem and changes the LNAB, then somebody else says, that's not proved, and changes it to Unknown again, and so on.