VMware got around this hidden cost partly due to the company's BYOD demographics, partly to good management practices.

Roughly half the employees in the BYOD program are in sales and already file monthly expense reports. This means the phone bill becomes just another line item. For employees who don't normally file monthly expense reports, they can collect wireless phone bills over a quarter and put them on a single expense report, thus reducing the accounting burden of processing BYOD-only expense reports.

BYOD also didn't lead to new hires or more management overhead. "That's all been baked into our program, and I feel very comfortable saying that I will save seven figures this year," Egan says.

Here Comes the Hard Part