The PBP suggests that when you want to reverse a scalar, you explicitly state this with ‘scalar reverse $variable’ instead of just using reverse on it. It suggests this both makes explicit, and regularizes the use, regardless of the context it is called in.
I don’t like this suggestion and don’t feel it is needed, but I won’t object to it because of the clear example in the book that makes it clear how it helps. I find the demand you add a ‘scalar’ all the time because sometimes it’s unclear to be a problem. I’ll probably turn off the critic warning for this, but I won’t say it’s too horrible.