David Letterman’s recent revelation that he had sex with subordinates is just a high-profile example, say employment lawyers, of a pervasive and potentially explosive problem: bosses having relationships with lower-level employees.

“It’s not illegal. It’s just dangerous,” said partner Andria Ryan of Atlanta’s Fisher & Phillips, noting the lawyer in her saw red flags when she heard about Letterman’s situation. “Most of the public looks at [the Letterman scandal] and says, ‘Oh, what a shame for his wife, his family or his job.’ My first reaction was, ‘This is a sex harassment suit waiting to happen.’”