We can certainly do it well in advance of the flight so long as information is transmitted to us. For instance, at Air Canada we use the aeroplan number as a differentiator to determine identity, whether you are who you say you are. But yes, it is our intention, absolutely, just for the sake of good customer service, to identify as far in advance as we possibly can that you are not an exact match to that U.S. no-fly list.
On November 23rd, 2010. See this statement in context.