"How do you prevent an army of users with data on their own phones and tablets from strolling off with your intellectual property? The answer is mobile device management (MDM)."
MDM is a solution looking for a problem. Anyone with half a brain who plans to leave the company will already have a USB drive full of all the important documents and emails they need, regardless of whether it's against company policy. Remotely deleting their email app is merely closing the stable door after the horse has bolted.