One of Bierma's readers asked how "canvass" came to mean "a solicitation of votes or orders" or "an examination or discussion" from its original meaning, which was "to toss a canvass sheet...to blanket, as a sport or punishment." Bierma says that the violence of the action led it to more broadly be used to mean "attack." He sites Sir John Hayward (1599) saying, "The north parts were many times canvased, and...almost consumed by the Scots."

But Bierma wonders how the word evolved to mean both soliciting and verifying votes. Apparently the OED admits that this development hasn't been explained. Bierma assumes that the idea of covering a voting district came about as a metaphor for spreading a sheet over it, so that no one is left out. What do you think?

I had always associated the term 'canvass' with the term 'blanket'-- pictured, e.g., detectives 'canvassing the perimeter of the crime scene' as a veritable horde of police personnel virtually blanketing the area with door-to-door inquiries

However. I was intrigued by the expression used in all the etymology links, 'tossed in a canvas blanket.' This sounded like it might refer to an antique sieving or sifting method (passing though canvas), which could be construed abstractly as thorough examination, gleaning.. which at least sounds closer to the idea of gathering opinion. I found this interesting link-- only 1 page is accessible, but it helps:
.canvas-tossing

It sounds as though 'casting in a blanket' is not a punishment in itself, but rather a bit of midwifery supposed in old times to hasten labor. The idea that this might be harsh punishment seems to relate to this particular work (Segunda Pastoral), wherein the treatment would be used to humiliate the male offendors. Just as I reach the 'inaccessible' part, the author begins to bring in the 'sifting, straining' allusion of canvas. Perhaps one of you belongs to a philological society which has access!

The Inupiat and other Alaskan tribes think the blanket toss (nalukatuk) is great fun.

Eskimo Olympics

Now if only those blasted door-to-door 'canvassers' offered such sport!

Myth, what a great site. Did you see that ear pull?! Amazing!