When a company buys mobile devices in bulk, it can set up a process to automate deployment and management in a scalable way. In a BYOD scenario, an IT person has to input each individual device into a system, punching in phone numbers, IMEIs (international mobile equipment identity), and employee information.

Aberdeen doesn't provide a cost to this labor-intensive practice. Nevertheless, "It's a pretty realistic pain-point for a company dealing with BYOD on an ongoing basis," Park says.

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Then there's a boatload of security and compliance costs associated with mobile BYOD. Typically, BYOD brings iOS iPhones and iPads into BlackBerry shops. This means CIOs will have to invest in a multi-platform mobile device management solution and other software, maybe even a VPN (virtual private network) layer.

"The cost of compliance--ensuring governance, risk management and compliance--is also more difficult when devices must be chased down individually," Park says.