Hi Mxolisi,
My unlock-method also doesn't throw a RNFE, my isLocked-method does. And in my opinion the isLocked should throw one, because it is a requirement (but not a must one):
Any methods that throw RecordNotFoundException should do so if a specified record does not exist or is marked as deleted in the database file.
I explained also in my choices.txt why the unlock-method (and also update and delete methods) don't throw a RNFE. So if you explained in choices.txt (which is the location where you have to explain your decisions), you'll be fine because you don't violate any must requirement.
Kind regards,
Roel