One more note on the subject, there are 'knock-offs" very often a popular fabrics will be immitated just to the point of a copyright infringement.
I have found a few "knock-offs" at Joanns , one was a Hoffman Christmas print. The Hoffman was fabulous , but on very close inspection the prints design was off just a bit and the Hoffman had 19 colors in the registration on the selvage. The JoAnn version ( knock off) had only 10 . The cheaper knock off appeared "flatter" in color depth and intesity. .... and yes the fabric it was printed on was much much thinner. But from a distance of about 6-8 ft ... it would be tough to tell the two apart unless they were side by side.
There was a popular Kaufman line they printed lots of colors, Jo Ann's had a Knock -off , the print again similiar but not the same number of colors used in the printing , cheaper fabric, and no where near the color choices. .... and just to the edge of a copywright infringement.
As for the "trial " runs being sold ... I know no manufacture that engages in selling a less than exceptable fabric that meets their standards for quality ... the damage to the brand's reputation is not worth the few $$$ in fabric used.