Discerning between those to whom you should and should not explain the teaching

In this section of Book 1 of The Great Treatise on the Stages of the Path, Gunaprabha's Sutra on the Disciple is quoted, listing among others, not teaching to one "whose head is wrapped up in a cloth".
This point is not explained in the endnotes.
I can see that many of these refer to individuals with an improper disposition, showing improper respect or simply, and so on.
Does anyone have any insight into what the head wrapped in cloth refers to?

Note - I find it interesting that all of these restrictions are nullified by the recipient being sick.