expiry-interval & grace-period

Hi 

 

I've been told that if we don't change password and the grace-period is over, the device (NN3820 in my case) needs to go back to the factory for security reasons for resets. I can't find any information about this on the documentation. Can someone please confirm what happens if we forgot to change the passwords and the grace-period is over? Is there any scenario the box needs to go back to Acme for  resets other than faults? 

 

cheers.