With the US moves recently threatening importation of oil produced from the Alberta Oil Sands, Canada with all due haste should commence the process of improving their marketing options. Such would of course include opening the potential to other markets so as to reduce vulnerability to any one market. The concept of over depence on any one customer is and always has been considered to be by marketing savvy people, an approach which can be a business life ender.
Keeping ones options open as to who your customers will be, is not only wise business policy, but is vital to long term profitability and survival!
Brian