I have participated in the 1.5 and 2.5" swaps. I have wondered what others think if they happen to get 1.5 and 2.5 from me that are the same fabric. At first, I tried to keep the fabrics seperate, but I have done so many swaps now that I have lost track. So now I make sure that I cut some new fabric for each swap. That way I know there will be at least some that are different.
I agree with Wardy74, though. It doesn't bother me when I get the same fabrics in both swaps. I am just looking for more variety than what I have on my own.