Heather, probably b/c canvas bags are the best, I'm guessing.
I always ask the bagger to give me paper bags b/c I use them to put all of my paper recycling in, and then I recycle the entire thing. I hate seeing 320498203948 paper bags leaving walmart and all of the other stores every day. You guys all seem conscientious, but most of our world is not, sadly.
I'm kind of obsessed w/ recycling.