OK I think I have hit upon a simple brute force solution to all this rubbish that has been driving everyone nuts for years, myself included.

I have taken a complete directory contaning a 1.39 install and done a bulk find and replace of every instance of 'NONSSL' with '$request_type' (yes I know that this bull in china shop move lacks elegance - but hey warning folk not to buy stuff is really offensive IMHO).

Then a bulk find and replace of every instance of ), 'post',
with , $request_type), 'post',

Then a bulk find and replace of every instance of
$request_type, $request_type), 'post', with $request_type), 'post',

Closed all browser sessions on the site and tested it.

SO FAR nothing has broken, and on the contrary I have a completely functional site moving from HTTPS to HTTP and back again via numerous sequences of forms including searching, adding products from search results, and back tracking from checkout to add extra items etc without any weirdness or error messages whatsoever.

I would be very grateful if anyone can discover a problem with this or confirm that this is in fact the industrial fix that it appears to be. Added to which I am sure it is worth coming up with a more refined NONSSL replacement term that just bulldozing the lot.

FYI I used the source code search in Dreamweaver across a folder to achieve this - probably many other editors can do the same job.

Hope it helps. (Oh and don't blame me if you did not back up everything first).