Well yes, just the same as building a garden wall can make it harder to get into your house, if you forget to put a gate in it.  Doesn't mean you shouldn't do it - just do it properly.  And even the simplest code isn't necessarily going to help the reader understand why the code was written, or when, or by whom.  I agree that comments such as  -- clear the table in front of a TRUNCATE TABLE statement aren't helpful, though, and just add to the noise.

John