Employees couldn't opt out of BYOD, either.

Egan chose a BYOD mandate over a BYOD option because it was simpler. Having a mixture of company-owned phones and BYOD phones is a managerial nightmare, he says. With company-owned phones, Egan had to deal with broken phones, wireless contracts and deploying phones to new employees. (Half of VMware's employees have been hired in the last two years.)

On the day Apple released the iPhone 4, for instance, Egan says he received a hundred phone calls from employees telling him that their current company-owned phones needed to be replaced. "Let's just say there was a coincidence on major phones shipping and either damaged or lost equipment," he says, adding, "You can't be hybrid in this."

From an IT standpoint, there is little difference between a company-owned iPhone and a BYOD iPhone, says CTO Aaron Freimark at Tekserve, a services firm helping Fortune 1000 companies adopt the iPad. Employees will use consumer devices in a personal way, no matter who actually owns them.