The article is a bit vague. And the word "should" really should not ever appear in any liturgical documents. "Must" and "will" are the way to go. Should invites abuse.
And the word "should" really should not ever appear in any liturgical documents. "Must" and "will" are the way to go. Should invites abuse. "Should" is common in Church documents, even those prior to Vatican II.
"Must" is appropriate for the military, law enforcement, and children. And "must" doesn't prevent abuse, if someone is determined to abuse.