I use Cosplay Day Out as the name for events I run, but also for sales, and have it registered as a DBA. A couple of other local people thought it was cute and started using it for events. I politely sent them letters explaining that trying to emulate me rather than be individual would not only hurt my business ventures, but theirs as well, because it would cause confusion. And that, furthermore, it could cause a hassle come tax time if someone did the research and saw that there were other events under the name that I did not file about, which could cause me to get audited, and that they were welcome to keep using the name if they wanted to pay my taxes. haha. Every time it worked and they stepped back and made changes. I am saving to TM so that it will be easier to avoid in the future, and so that I have a solid legal standing, but for now being nice and asking has been effective. Maybe if you went this route, and explained how her trying to be you will hurt her business, maybe she will see the light.
