I informed the manufacture and their response was that I was the first to complain; however, they promised to investigate the issue and possibly revise the design. Fair enough. But not an immediate remedy.
Liking the bag and wanting to use it, I did what I suspect any other red-blooded American would do: I searched Google for help.
Introducing Strap Gummy, “The invisible non-slip shoulder strap solution.” A pack of six set me back twelve bucks (including postage) and let me tell you, they are worth every penny.
A Strap Gummy is a 5-inch strip of high-friction silicon that’s 7/8ths of an inch wide and has adhesive on one side. It looks like a translucent Band-Aid. Peel away the release paper and press it into place. It provides enough grip to keep the strap on my shoulder—without feeling tacky to the touch.
The Strap Gummy, which is clearly marked “Product not for consumption,” can be removed if first heated by a hair drier. Or at least, that’s what the package says. I don’t think I’ll be removing it, because (so far at least) it works great.