I found that when I pressed/ironed fabrics that were sopping wet from starch or sizing that they stretched.
I've since been told that one should starch, then let the fabric dry, and THEN steam press.
My personal belief is that fabrics should have good manners "on their own" - they should NOT need to be washed with synthropol or retayne or color catchers (after the quilt is made) nor should they need to be starched or sized to have decent body to work with.
I will concede using starch lightly to stabilize pieces cut on the bias.
To find out if fabric has good manners, I wash and dry it before doing anything else with it.
My opinion. And I feel strongly about it.
And there are others that say they have had no problems with using fabric "straight from the store"
I'm not going to change their minds. They are not going to change mine about this.
I have had some "bad experiences" - which is why I feel so strongly about it now.