Including a statement that the item being sold is in no way connected with whatever 'licensed' team, group, etc. creates a transparency it is helps to alleviate confusion when selling the item. NOT including the name of whatever 'licensed' group is printed on the fabric is also a good thing.
One may NOT mass produce items created with 'licensed' fabric and sell them.
The copyright/license means YOU can't reproduce THEIR fabric...doesn't mean YOU can't create something from their fabric and sell it.
A lot of information is simply scare tactics, if not outright stupidity.