That is explicitly forbidden on Unsplash, along with anything else that paints the models in a bad light. I've even wondered about an author who uses someone else's image as his avatar and then occasionally, writes about his sexual exploits, usually in a humorous way. I wondered if that might get him into trouble, because it insinuates that the model in the picture used a prostitute, for example. Which some might say doesn't paint the model in a fabulous light. I reckon animal photos are safer.