Unfortunately, it is not uncommon to see slides, handouts, lists, etc. that others have created without any mention of the original author. It is not only disappointing, folks, it is ethically wrong. If you use someone else's work, you need to provide a citation. If you "adapt" something, you still need to provide attribution. AND-- YOU. CANNOT. CHARGE. MONEY. FOR. IT.
This is not the only ethically corrupt behavior I see. I watch folks use their phones to record presentations. Not just snippets, but entire presentations. If you have permission to do so, that is fine. But without permission, again this is ethically wrong. When I say something to the offender, I am met with, usually, an angry retort along the lines that it is OK because they are just sharing it with kids. IT. IS. NOT. OKAY.
It is not okay to record presentations. It is not okay to copy materials that do not belong to you. It is not okay to make copies of books. It is not okay to sell ARCs or F&Gs (and I know there will be tons of folks who argue this point as they do every time I post about it) as they are provided to us free of charge.
I think part of this total disregard of copyright and ethics harkens back to the days of music piracy. I constantly had to remind the former residents of the back bedroom that they could not burn CDs of their music to share with friends and vice versa. In doing so, they deprived the artist of royalties. The form residents of the back bedroom, and their peers, believed it was OK, that artists made enough money anyhow, that they were doing nothing wrong.
As someone who has written a few books, I know that royalties are never going to be my retirement income. But I do appreciate the checks when they arrive. And I have another full-time job that can pay the rest of my bills. But for some, royalties are their salary. Copying books, stealing ideas and documents, deprives the author of her or his just due.
Please feel free to share materials with others. But, please, give credit to the author. And be aware of copyright. Speak up when you see anyone violating the law or even the spirit of the law. You are more than a model of literacy in the classroom. You are also a model of ethical behavior.