Yes, third parties can present evidence to examiners to prevent trademark registration.

During the review process for a trademark application, the United States Patent and Trademark Office (USPTO) will consider any relevant evidence that is presented by third parties, including evidence that suggests that the trademark is not eligible for registration.

Third parties can present evidence to examiners in a variety of ways, including by submitting a letter of protest or a third-party submission. A letter of protest is a written communication from a third party to the USPTO that raises concerns about the trademark application and provides arguments or evidence in support of those concerns. A third-party submission is a written communication from a third party to the USPTO that provides evidence or arguments that may be relevant to the review of the trademark application.

Third parties can also present evidence to examiners by opposing the trademark application during the publication process. After the trademark application has been examined and approved for publication, it will be published in the USPTO’s Official Gazette. This allows other interested parties to oppose the registration of the trademark. In order to oppose the registration of a trademark, a third party must file a Notice of Opposition with the USPTO and provide evidence and arguments in support of the opposition.

It is important to note that third parties may only present evidence that is relevant to the review of the trademark application and that raises legitimate concerns about the eligibility of the trademark for registration. It is a good idea to consult with a trademark attorney or other professional to assess the options available for presenting evidence to examiners and to determine the most appropriate course of action to take.