There’s flirting and then there’s sexual harassment. If the flirter is a supervisor, it’s probably sexual harassment whether or not there was any physical contact.
The best approach: Set a strict no-fraternization rule for supervisors and subordinates.
Recent case: While Stephanie was working on her Ph.D. on birds of prey, she took a university research job that involved several trips from Minnesota to Alaska. Her supervisor for those trips was a renowned raptor specialist.
The research took place in a remote area of Alaska where Stephanie and her boss slept in tents. They were the only humans for many miles around. While on their first trip, the supervisor took a photograph of Stephanie while she was bending over a raptor nest, asked her about her dating history and suggested that they could be more than just research partners.
Before their second trip into the wilderness, he suggested that they pack just one tent. He told Stephanie that since he was her supervisor, she had to make the first romantic move.
Stephanie complained about harassment to the university. The supervisor admitted he had flirted with her with the hope they would become more than friends and research partners, but denied touching or otherwise harming her.
She sued anyway, alleging sexual harassment.
The court said Stephanie’s case could go forward even though there hadn’t been any touching or blatant, sexualized comments. (Jenkins v. University of Minnesota, No. 13-1548, DC MN, 2014)