This must vary by region. We get paper bags with a reflective liner. They’re re-usable if the super adhesive they use for the label stickers doesn’t require ripping the bag apart to open it, but they’re definitely intended to be disposable. Sometimes they just use regular paper bags and let our stuff get warm. It seems random whether they stuff the bags to the gills or have a single item per bag. This happens with both Fresh and Whole Foods.