The old thread (we'll forget about the short-lived duplicate, though of course that's still in the archive here as well) is at  Origins: 'do not be offended, please' (Song)

The Roud Folk Song Index assigns it to number 12785; just one example at present, in Pankake, Prairie Home Companion (1988) 180-1: text and music from Garrison Keillor, title How Pleasant That Would Be. Apparently no indication of prior source.