To take the other side....the possibility exists that the Bills did have a convo with the Cards earlier in the summer and they have since moved past the point of making a move on ANY QB...especially one with questionable talent like Leinart. Given the place that the Bills are currently, with a starting QB who has high confidence and has had some success in pre-season..it would seem natural that the Bills would want to squash any rumor of dissatisfaction, so they don't damage what they have already built up during the pre-season.
They don't really have anything to gain by having their name attached to Leinart, but could possibly lose something if their starting QB starts questioning his confidence and leadership that the staff has been trying to build up with him thus far.