I’m a “DISigner” on the DISboards, and we make free Disney designs for people all of the time. Disney doesn’t mind - as long as they are not sold, since it’s illegal to sell copyrighted material without permission.
So people can take our designs and print them out and iron them onto shirts or whatever, but if they took them to a screenprint shop, they’d likely be turned down (especially if they were then going to sell the shirts).
However, there are some Etsy designers who sell copyrighted Disney material. If Etsy becomes more mainstream, I think Disney will crack down on them.
Also, the Delta-Sigma sorority on campus uses the Disney font for some of their shirts. And our high school special education class went to Disney last year and made shirts with our mascot wearing Mickey ears and it said “Dogs go to Disney.” I think as long as it’s in a specific area like a school and not mainstream on the internet, it is okay. That doesn’t mean it’s not illegal - I just don’t think Disney cares about it if the people doing it aren’t profiting very much.
A seamstress friend of my mom wrote a book which was apparently very popular in the sewing world. In the book, she referred to a certain fabric store as “the Disneyland of fabric,” and Disney made her remove their name or pay licensing/copyright/whatever fees.