This statement has some inaccuracies in it, it is true that it will literally result in more oil from other places, but, given supply and demand, it will result in less additional oil from other sources.
Whenever a cheap source of a good is eliminated the average production price of that good is increased (assuming there is an exhaustible supply of that good at that price) so the removal, or even inconveniencing of access, to tar sands extract will cause an up-tick in prices overall and a likely unnoticeable dip in supply.
Additionally, as a Canadian myself, the Alberta oils sands have recently contributed strongly to an economic crisis in Calgary as extraction profitability has sharply declined. There is a lot of oil still left up there but Alberta needs to act now, while it has the funds to do so, to transition their economy. It is not a feasible long term revenue source.