USB data blockers are good, but they're reliant on the employee actually using them. A DLP solution such as MobileIron forces compliance, by locking corporate resources behind a secure application. For example: Users any mobile device policy, such as BYOD, CYOD, and COPE. If they want to access their corporate email on their phone. They will need to sign into the MobileIron application, in order to be granted visibility to their corporate email account. Since the emails are being read/sent through the MobileIron application. Safeguards can be applied even on an outside network-mobile level. If an employee attempts to send a customers social security number, the MobileIron will either block it, alert it, or both, contingent on how the company setup the MobileIron service to work.

https://oroinc.com/b2b-ecommerce/blog/testing-and-staging-environments-in-ecommerce-implementation/