Canadian entering on B1 if TN is denied?

I am starting a new job next month. I will be flying from Vancouver to the US at the end of this month and plan to apply for TN there. However, if the TN is denied for whatever reason, can I ask the officer to let me in on a B1 instead on the basis that I plan to come back in a week to reapply? Or will they find it suspicious and refuse to give me the B1?