Office romances are nothing new. Why are they still so complicated?

The affair between Norfolk Southern Chief Executive Alan Shaw and the railroad’s general counsel is the latest in a long series of incidents that have tested corporate politics and caused trouble for internal companies.

Shaw was fired Wednesday night after a board investigation found that the relationship with Nabanita Chaterjee Nag violated company policy. Nag was also fired. Neither responded to requests for comment.

Employment lawyers like to say that office love and lust aren’t illegal—they’re just usually not a good idea. In the wake of the #MeToo movement, companies have tried to set clearer guidelines for workplace relationships, though corporate advisers say many companies still struggle with how to respond effectively.

Most employers prohibit managers and upper management from dating their subordinates to avoid a power imbalance, but they are usually much more open to lower-level employees dating.

The reason? Many people meet their partners in the office. A study conducted earlier this year by SHRM, the society of human resource managers, found that about 20% of employees had gone on a date with a coworker in the past year.

“It’s always going to be there. It’s where people come together,” said Deb Muller, CEO of HR Acuity, a technology platform that helps companies track employee investigations and complaints.

There is little evidence to suggest that relationships between bosses and subordinates are growing, although advisers say boards now generally have less tolerance for what they perceive as bad behavior by executives. When relationships are discovered, they are often quickly resolved.

McDonald’s in 2019 said it had fired then-CEO Steve Easterbrook over his consensual relationship with a female employee. In an email to employees, McDonald’s said he had violated the company’s policy on personal conduct.

BP issued new workplace relations policies earlier this year, following the departure last year of CEO Bernard Looney, who resigned after the oil giant said he had not been fully transparent about his past personal relationships with co-workers.

Corporate policies toward executives are more conservative than in the past, when some CEOs married their secretaries, said Johnny C. Taylor Jr., CEO of SHRM, a human resources group.

If a management executive begins dating an employee now, it could expose the company to future lawsuits and other risks.

“There’s zero tolerance for the distraction and reputational risk that comes with allowing a CEO to date someone at work,” Taylor said. “There’s a question of judgment.”

Many boards, he said, are essentially telling CEOs, “We’re paying you enough money to find a date somewhere else.”

Workplace romances involving an executive are often poorly guarded internal secrets, said Muller of HR Acuity, and can lead other employees to come forward with complaints about favoritism within the organization. “You can’t ignore the power plays that can be going on,” she said.

For the rank-and-file, companies have realized that it’s not practical to completely restrict consensual dating. Some have tried to set clear guidelines for what’s allowed. At Meta, Facebook’s parent company, for example, employees have to follow a simple rule: You can ask someone out, but only once. The social media giant has said it wants to prevent unwanted flirting between coworkers.

“If you ask a coworker out on a date and the invitation doesn’t result in a date, don’t ask again,” Meta’s relationship guidelines state.

Meta also says that coworkers can’t ask someone out on a date if they’ve never met. “For example, it’s not appropriate to find someone on the wiki and message them or otherwise contact them to ask them out on a date or tell them you find them attractive,” Meta’s rules state.

Like many employers, Meta also has requirements for when a relationship must be disclosed to HR — documents that are sometimes derisively called “love agreements.” If a relationship breaks up, there are guidelines there, too.

If a relationship ends, Meta notes, “you need to maintain professionalism toward each other at work.”