Is this the same mechanism?
So far I haven't had any problems with it, although I have only been using this for few hundred miles with heavy contents. However, I know that the previous owner used this for around 10k miles, and I assume he would've trashed it if the mechanism had failed. And it doesn't have any straps to begin with.
Perhaps if your tank bag has additional rings like mine does you could cut the straps and use them only when you've loaded the bag very heavily?