This unit doesn't use software encryption like Buffalo SecureLockWare, it is based on hardware encryption, which doesn't allow the password to be removed!
Is there any way of resetting the password if it gets lost?
There is a function to reset a password for Windows and Mac OS X, check the manual on the utilities drive, point no. 5.
This reset will delete all content on the unit!
Could an enduser open the case to retrieve the data and stay within warranty?
No, the customer cannot open the case. Opening the case will void the warranty.