Most people in the community know about the Cosplay is Not Consent movement that has hit the internet and conventions by storm over the last few years. If you don’t, the simple answer is that no matter how you’re dressed, no one has permission to talk/touch/act any way towards you that makes you uncomfortable. It became viral in 2013 with a video made by Sushi Killer, and became widely used throughout the community, either at conventions, on merchandise, you name it.
As of November 22, 2016, the phrase is now showing it has been trademarked and per a statement by Cosplay Deviants CEO, Troy Doerner, the company is the one to have done so. He states it was done after a large convention wanted to buy the rights to the domain under his control for Cosplay is Not Consent, so he chose to trademark to avoid conventions from profiting from the movement. He also stated that he still wishes for conventions to push the Cosplay is Not Consent movement, however, to allow them to be listed as the spearhead and basically get advertisement for his company for it.
If you want to read more about the situation, and possibly arguments for why Cosplay Deviants may not be the first to coin the phrase, check out Bleeding Cool’s article here.