Just a techy update on this, both Honeywell and Thales, the FMS suppliers for Airbus are working on versions of their FMS systems in which one of the improvements will be a feature that secures take off performance. It basically introduces a rough error check to prevent such large errors being entered into the FMS.
I think both are due for certification next year and whilst newer aircraft it will involve just software updates some slightly older FMS installations will require some hardware and the software changes and on the really old Airbus FMS systems a complete retrofit of the system will be required.