IT managers who provide mobile devices to their end users can be like parents who let their teenagers take their cars at night. You start to wonder what they're up to moments after they leave.

The security risks of mobility have been much discussed. After all, laptops, smart phones, handhelds and other mobile devices often carry confidential or even regulated information, and these devices are easily lost or stolen.

However, a new risk to the enterprise is emerging: Employees who misuse their mobile devices. Increasingly, mobile workers are being tempted to download and watch movies and TV, listen to music, gamble, access pornography and do other things they shouldn't be doing on the company dime.

"The threat to organizations is very real," said Derek Kerton, principal of The Kerton Group, a telecommunications consulting firm. While the threat of abuse of mobile privileges is growing, it isn't entirely clear what to do about it, Kerton and other experts said.

How serious a threat?

Companies have long used tools that filter e-mail and limit Web access by deskbound employees. However, the misuse of mobile devices is just now emerging with new technology.

"Three years ago, we weren't having this conversation," said Michael Voellinger, vice president of wireless services at Telwares Communications, another telecommunications consulting firm. "It's a very significant risk now because of how fast the [mobile] content base is growing and how fast device capabilities were growing."

Specifically, cellular operators have widely deployed 3G cellular data networks in the past two years that deliver typical download speeds of 500Kbit to 700Kbit/sec. The operators, anxious to both wring revenue out of those expensive networks and combat stagnant voice revenues, have launched multimedia services such as downloadable music, streaming video and even live television. Many new mobile devices are designed to be used with these services.

In addition, new media services not designed specifically for mobile users, such as Amazon.com's new Unbox movie-download service, enable users to transfer movies from desktop PCs to mobile devices. And, of course, the purveyors of pornography and gambling are busily exploiting this trend.

The most often-discussed threat to the enterprise is loss of productivity. For instance, what if an employee is watching a movie when he or she should be working? Kerton noted that research he did with a South Korean cellular operator confirmed how much a peril this is.

"The company launched mobile video, and we did a survey on usage patterns," Kerton said. "The expectation was that there would be heavy usage during commuting hours and moderate use the rest of the time. But the heaviest usage was in the afternoon and evening. We surmised that use in the afternoon was people watching movies at work."

In addition to loss of productivity, there's a financial risk to enterprises.

"None of these services and devices are free," Voellinger said. The lack of productivity translates into dollars, he added.

"If an employee is doing something he shouldn't at 10:30 in the morning when he should be working, that equates to dollars at the end of the day."