From BB Network
"Do I need to cancel my subscription at the end of the season?
No. CBS will not charge your credit card past the end of the season. If you signed up for the season pass, especially smart to do with the Early Bird pricing, then you’re “one and done” with payments. There are no further charges. If you signed up for the monthly pass then you will be billed once a month until the season is over. Access will conclude on October 20, 2013."
So no worries about having to cancel, rebilling etc.