Can an employer tell you whom to pal around with after work? Could you get fired for going to a co-worker's Fourth of July barbecue? You could if you work as a security guard for Guardsmark LLC, the big security company that employs guards just about everywhere (including at The Washington Post).

The National Labor Relations Board on June 7 upheld a Guardsmark rule that stated "While on duty you must NOT . . . fraternize on duty or off duty, date or become overly friendly with the client's employees or with co-employees."

Yikes. So many issues here, so little time.

Guardsmark says it needs this regulation for added security: "A security officer who is overly familiar with a fellow security officer or a client's employee may overlook signals that, if detected, could be instrumental in preventing workplace violence."

But can a company really dictate what we can do outside work? Well, until June 7 rolled around, it probably couldn't. But now, the labor board has set a precedent that could really hurt our workplaces, morale and culture.

Will the ruling have the opposite effect and actually hurt morale and make guards less likely to discuss issues and possibly find new ways to protect the buildings in which they are stationed?

The Gallup Organization has studied workplace friendships and says that those who have friends at work, with whom they socialize both in and out of the office, are more engaged than those who don't. Studies have also shown that having friends at work lowers turnover and increases safety.

When I wrote a column about workplace friendships almost a year ago, Curt Coffman, a global practice leader, told me about a presentation he gave to workers at a manufacturing plant in Texarkana, which is on the Texas-Arkansas border. He told them having a best friend at work cuts down on safety incidents.

It was not news to the group of workers on the shop floor. One said to him: "Son, if the guy that goes walking across the floor not wearing safety goggles is a best buddy of mine, I say, 'Get your damn goggles on.' If I don't know him, I won't say it."

Danielle Marie Gibbs, who works for Sprint Nextel Corp. in Reston, said friendships are important to her well-being at work. She calls one of her co-workers her "office dad." Although he has several children of his own, he offers Gibbs advice and even helps her with car problems. He is just one of several people she considers friends or with whom she socializes outside of work. "I have worked with people before who want nothing to do with you at work, let alone outside of work, but I believe that Nextel is truly an environment where they foster teamwork. And how can that team atmosphere not lead to outside friendships?" she wrote.

Perhaps this was best evidenced by her co-workers' reactions after she was in a car accident in June. Knowing she has no family in the area, her co-workers brought her food and rescued her belongings from her damaged car before it was towed away. Without them, she said, she doesn't know what she would have done. And she likes to point out that she has been there for only a year.

Sure, having friends at work can also trip up employees. How many times have you been ignored by a cashier because he was busy flirting with a saleswoman? And sometimes those office friendships can be trouble in other ways. Just like friendships formed in other parts of life, some work out and some don't. But at work, it is important, many have discovered, to be careful about those with whom they socialize.

"I am new here, and after my second week, one of my new co-workers invited me out for drinks," wrote one woman who works in human resources and spoke on the condition of anonymity. "Turned out she's a disgruntled, recently (rightfully) disciplined employee searching for an ally, and she filled my head with poisonous half-truths about the company."

And so the woman who is new to the company is living by her personal rule: "Select any work friends very carefully. The one woman I hang out with now works in another department and seems to have her head screwed on carefully. I avoid people who might have an agenda or who want to be my best friend forever."

Most companies trust their employees to figure out what is good for them and the company, and what isn't. Take Denise Newman, for instance. At her previous firm, where she worked as a legal assistant, she became friends with the human resources manager. They lived in the same neighborhood and belonged to the same gym. The manager was concerned "about how other staff members and the firm administrator would interpret the friendship" because the manager didn't want it to look as if she had chosen a favorite.

So when the two went to classes together at the gym, they did not leave the office together. If they wanted to go to dinner, it would be in their neighborhood rather than near the office.

"It made her comfortable and allowed us to be friends," said Newman, who now works at a different law firm in the District.

Bridget Pople, who used to work for a District fundraising firm, was part of a staff of mostly twenty-somethings who socialized a lot outside of work. Being new to the city, and to the working world, the social group was more than just fun. It helped the workers navigate a new place and a new kind of life.

And her boss seemed okay with the intra-office friendships: "As far as I know, the head of the firm didn't care that we were all so social," said Pople, who has since moved on to a job in Atlanta. "I think she liked knowing that we enjoyed coming into the office every day."

I wonder how those Guardsmark workers feel about coming to work every day.

Join Amy Joyce from 11 a.m. to noon Tuesday at to discuss your life at work. Lots of people talk about how they hate their jobs, but rather than figure out how to change things, they are ready to jump ship. I want to talk to those who reinvigorated themselves in their jobs while staying in the same positions. E-mail your responses to