Both the kits I ordered were quite generous with the fabric. On one I had so much I used the fabric to make two completely different quilts.
I think it is good will on the suppliers part because a large percentage of quilters will not get to that kit for quite a while and the fabric will be long gone in the event you make errors and require more. I purchased both my kits on clearance but have noticed there is usually quite a premium at regular price, even taking into consideration the pattern cost.