A would-be owner of an herbal supplement store recently learned how to convince a judge you’ve got permission to use another person’s intellectual property. You actually have to bring evidence to court. Call it a rule of thumb.

Novus Optimum Labs is a San Francisco based company that sells herbal supplements. Novus hired a woman named Gina Tamayo to work as an assistant to Meliza Reyes, the company president. That did not go so well.

Tamayo accused Celso Reyes, Meliza’s brother, of sexual harassment. The company terminated Celso, and Tamayo got a restraining order to keep him at bay. But Tamayo did not sue Novus.

Tamayo did, however, leave the company and with her husband opened a store called Novus Opti-Lab, which sold Novus products. Tamayo also sold the products via a Web site – novusopti-lab.webs.com.

Tamayo's activities didn't sit too well with Meliza Reyes, who brought a lawsuit alleging an intellectual property trifecta. The complaint included claims for trademark violation, copyright infringement and cybersquatting.

The trademark claim contended Tamayo used the Novus mark in a manner likely to confuse consumers. The copyright claim alleged Tamayo copied content from the Novus Web site. And Reyes claimed Tamayo’s domain name violated the federal Anti-Cybersquatting Consumer Protection Act. Reyes asked for a preliminary injunction to stop Tamayo from using the marks, the Web site content, and the domain name.

Tamayo didn’t deny she created and used the infringing material. Nor did she argue that her use wasn’t confusingly similar. Her only defense? She claimed Reyes had consented to Tamayo's use to settle the harassment dispute.

Tamayo's defense didn’t fly with the court. She offered no evidence other than her own statement. She provided nothing else to establish consent or any ongoing business relationship. It’s fair to assume that had there really been a settlement or an actual business relationship somebody would have documented it in some fashion. An e-mail at least.

Given the sheer lack of evidence to support Tamayo’s lone defense, the court had no choice but to grant the injunction. The injunction was “preliminary," meaning there may be more to come. But this may be all Reyes really wanted.

The lesson here is simple. Intellectual property rights are valuable. So if you think you have an agreement with someone to let you use theirs – better document it. As you can see, courts kind of expect it.