> FYI it is literally required by law that, to maintain a trademark, the company with the trademark must actively enforce it on an ongoing basis. Even if this side-project was benign, Waffle House must send cease-and-desist letters to maintain their trademark generally under US law.

That's not the only option available. They can, if they find the use of the trademark to be benign (or even beneficial), offer a license to use it for this purpose.

For example, the Linux trademark has an approval and attribution process: https://www.linuxfoundation.org/legal/the-linux-mark

Folks should consider hiring Jack Daniels' law firm. https://www.abajournal.com/news/article/jack_daniels_cease-a...

> In order to resolve this matter, because you are both a Louisville ‘neighbor’ and a fan of the brand, we simply request that you change the cover design when the book is re-printed. If you would be willing to change the design sooner than that (including on the digital version), we would be willing to contribute a reasonable amount towards the costs of doing so.