I am running the trial version of Smith Cart (4.6.0) and am unable to removed the Quantity from the Product List, unless I hide it in the cart also.  

That would be okay, but the documentation for the Hide Quantity checkbox for both the Product Detail Page (p215) and General Cart Settings (p229) sections say:

Hide Quantity – Check this box if you would like to hide the “Quantity” textbox on the product listing page and the product detail page. This is useful if your business only sells to resellers that require prior approval before buying your products.

It seems that the Hide Quantity option  for the General Cart overides the Product specific setting.  This is espcially confustion, as I have to check Hide Quantity in the General Cart setup, even though I am not using a cart.

The Product Details page hides if either the Product Specific OR Product Details page are set up to Hide the Quantity.  The selection on Product Details doesn't affect the Product Listing, regardless of what the documentation says.

Maybe an option would be to add the Hide Quantity options to the Product Listing subsection of the Cart Settings, as someone may want to show the Quantity in the cart, but no on the Listing Page.

Cheers