Playing with this more on my test site, I realize it's currently listing products that were "bought" together even if they're just added to a shopping cart by an anonymous user waiting to checkout. There should probably be a setting to exclude certain order status values, in addition to #629008: Add setting to exclude certain product classes for product classes. I've got the changes to the query done, I just need to add the setting to the UI. Patch probably sometime next week (I have a busy weekend ahead of me).