Starting in 2013 on the BX25D there has been a factory "shield" up under. While this is much better than NOT having a fan shield - it does not protect the $18 plastic fan perfectly.
If you are ever planning to go into a place where you run over sticks and debris - I would highly recommend the under armor by either of the companies that supply for the BX series. Even a MMM can have stick finds its way up under and catch a piece of that fan! As those that have replaced the fan - it is a royal PITA to fix.