The productivity p oblem
BYOD promised to make employees happy and more productive. After all, they could use mobile gadgets of their choosing for work and would carry those gadgets practically all the time, meaning that they'll be working in the evenings and on weekends. Worker productivity was supposed to spike.
Then some companies saw workers slack off by using their gadgets to check Facebook and play Angry Birds at work. This led to a few apps landing on the infamous BYOD blacklist.