An interesting thread - I am particularly from the fabric aspect.
Like others I agree we shouldn’t copy designs and either pass them off as our own. So no Mickey Mouse Ear hats, or VW Campervan glass art as Joy says. Or even less well known brands - I do felt applique on some of my products, in the early days I used to “copy” a motif from the fabric I was using, they weren’t exactly the same but close enough. Nothing is ever truly unique, we are all inspired by the things we see around us, but these were blatent . Needless to say I’m doing my own motif designs now (and still nagging my Dad for drawings so I can print my own fabric…)
The principle of first doctrine is interesting, and the links provided by Debbie @thecrimsonrabbit reminded me of some research I did many years ago when I first started using upcycled and vintage nursery fabric in my makes - I still have a load of Warner & Disney remnants that I bought but never used and am now selling as used fabric suitable for personal crafting through eBay. I bought them secondhand but I suspect they were duvets or curtains, so there is a change of use by someone else in the chain, which is controversial.
Back to my current makes, and whether it’s ok to use commercially printed fabrics in products to sell. I’m not talking about Disney, but everyday prints by big brands such as Moda, Liberty or Rose and Hubble.
I use a lot of quilting fabrics in my makes - very few have the “only for personal use” printed on one side, and I’m increasingly seeing that manufacturers are actually aware we use their products, and some are actually facilitating it.
As some of my makes are toys, I need to get the relevant certificates for the part 3 chemical safety aspect of the testing, and as this is much more stringent than the normal testing needed to sell fabric in the EU/UK, it’s not something manufacturers do routinely.
The groups I belong to pay for fabric/yarn to be tested ourselves - but we are finding manufacturers and suppliers are now replying to emails from small scale toy makers asking about chemicals used in the manufacturing. And a few are actually having the products tested themselves and selling it as EN71-3 compliant (Rose and Hubble is an example). They know this is in respect of fabric being used for items made for sale, as you don’t need these specific tests to make toys for family, friends or to donate, nor for any non-toy purpose.
Not all are so helpful - there will always be fabric manufactuers I avoid, and of course it certainly doesn’t apply to the characters printed under licence - whoever the manufactuter.
Now, does anyone want some Donald Duck remnants going cheap? For your own use of course!!!