Here's the Pattie Gonia vs. Patagonia tea.

Pattie Gonia and Patagonia basically talked long ago about her using the name, and Patagonia was like sure, yes, we love what you do. HOWEVER, you just cannot use the name in association with these specific classes without our consent. She did, and they asked her to not, and she continued, so they sued her for a dollar, because you have an obligation to defend your trademark or you can be unregistered for dilution.