Whatever the implementation on the back end, when you do get to see a bug which is a duplicate of another, it should be clearly visible that it is a duplicate.
It seems to me that the topic of this bug is a rather complex problem, if you look at the interactions between this bug, bug #61429. bug #50549, etc. I don't think it should be closed simply by hiding duplicates and/or asserting that people who need to see and manipulate duplicates can somehow find them by explicitly searching for them.
Whatever the implementation on the back end, when you do get to see a bug which is a duplicate of another, it should be clearly visible that it is a duplicate.
It seems to me that the topic of this bug is a rather complex problem, if you look at the interactions between this bug, bug #61429. bug #50549, etc. I don't think it should be closed simply by hiding duplicates and/or asserting that people who need to see and manipulate duplicates can somehow find them by explicitly searching for them.