Here's a
web site touting the service. (There are others.) Please note that this one has a link defending Q Chex. If we are known by the company we keep, I know as much as I need to know... They are apparently using the fax document only as a source of information to create a standard paper demand draft; i.e. they are not attempting to process the faxed image.
Obviously, this is not a service your bank would encourage someone to use. Most people don't buy carpet by fax and I'm a little concerned over anyone who wants to.
Ooh, ooh here's another one where they indicate that it's completely legal. So glad to know that.