It seemed like a good idea at the time.

Lynnette Simpson invited her husband and their 5-year old daughter along on a business trip to Norfolk. The plan was that after Simpson's business meetings were done, the family would turn the trip into a mini-vacation.

Instead, husband Steven and daughter Julia were stuck waiting -- and waiting -- in their hotel room or the lobby. Simpson's meetings and business dinners dragged on, hours longer than scheduled.

That was two years ago and Simpson's family hasn't joined her on a business trip since. "It was a bad idea. I walked them to a shopping center on Saturday and went back to my meeting. I hardly saw them," said Simpson, of Glover Park, a writer for the Society of Government Meeting Professionals.

For frequent business travelers, it can be tempting to bring the family along in the summer, when school is out and spouses want to take some time off themselves. It seems like a bargain when the company is already picking up the bill for the upscale hotel as well as your airfare. And sometimes you can use frequent flier miles for family members to fly free.

The Travel Industry Association estimates that about 10 percent of business travelers have taken their children with them on occasion, according to a 2003 survey of 300,000 business people.

But those who have been there warn that such trips should be carefully planned lest they turn into more headache than fun.

The biggest mistake, these travelers say, is to bring a child but not another adult. Bethesda frequent flier Ivy Harper has seen unchaperoned children at hotel pools and in elevators. Striking up conversations with the kids, Harper learned that many of them were visiting the hotel with a parent who was attending a meeting. Harper said children younger than 16 should have a parent or a chaperon with them.

"It's too dangerous to leave kids alone in a hotel," she said, "especially in a strange city."

Harper has taken her two young children on business trips. But when her husband has been unable to go with them, Harper has arranged for her mother to fly in from Lincoln, Neb., and meet them at the hotel to watch the kids.

Babysitters, of course, would be an option. But most hotels don't offer such services on site, mainly because of liability issues.

Park Hyatt is one exception. The hotel chain, which has nine properties in North America, offers child care for registered guests, said Hyatt spokesman Jamie Izaks. The price varies by city; in New York the hotel charges $21 an hour with a four-hour minimum.

At other chains such as Marriott and Hilton, the concierge can provide lists of baby-sitting services in the area. (Resort properties of these and other chains, though, often do offer on-site child care.)

Some travelers come up with creative strategies for bringing children along. When Jonathan L. Kempner, president of the Mortgage Bankers Association in Washington, has met clients out of town he sometimes has called ahead to see whether the client has children around the same age who could spend time with his.

Kempner said he has taken his daughters on about 30 trips during the past 10 years -- but only one daughter at a time, to keep things simpler. Sometimes he has called convention planners to see whether other children would be there -- and, if so, has asked whether a kids' event could be organized while the parents were in meetings.

Kempner has even taken his daughters on dinner "dates" with clients during trips. "It's a good way to cement your relationship" with your children, he said. "Kids remember when they go on a business trip with you."

For Washington attorney Jonathan Band, it's worth bringing children only if business meetings will be limited -- say, to half a day. In the past seven years, Brand has taken either his son or daughter to places such as Israel, Portugal, Las Vegas and San Diego. After finishing work, he allows the child to decide what to do for fun. So, in Portugal they ate at Pizza Hut and while in San Diego they went to Legoland.

Some business travelers who have to stay over a Saturday night to get cheaper airfares say they find it more pleasant to do so if they have their children with them. When going to cities where he has family or longtime friends, Web page designer Ted Anthony of McLean often takes one of his two small children. That not only gives him quality time with the kids but gives his wife, Susan, a break.

"My wife seems to appreciate it a lot more than any of us," Anthony said.