Yes, I see all that Stower. But, whatever the earliest versions might have said, the present fact is that the nakedness {STARK!} of the woman has become current and widespread in many [if not most] variants sung these days; & that there is plenty of traditional warrant [see e.g. my Sharp ref above from 1903] for this: so the question asked in the thread title remains a perfectly valid one.

My answer to the question is that it adds an intriguingly and irresistibly dramatic touch to the situation described; providing even more convincing motivation to the brave & philanthropic Johnson for his sympathy for and assistance to the woman.

~Michael~