Krashen has said:
“I think that many teachers simply can’t do non-targeted input because they are required to follow a grammatical syllabus.”
However, the grammatical syllabus is at odds with Krashen’s hugely important Natural Order Hypothesis — the concept that we acquire language structures in a fixed order that we do not know, and that cannot be accelerated or altered through conscious memorization and application of rules.
Therefore, if we are to truly teach for real, lasting acquisition, we can only do so by delivering the content in a natural way, which to me means in a non-targeted way.