Petzl i'D (Older model), What are the teeth for?

I was recently given some older rope access gear, which included a petzl i'D. Its been very useful dealing with thicker static ropes while doing route development, but it has a feature I've been unable to identify the usage for. The petzl website technical manuals don't describe it and I can't find an older manual.

There are spring loaded teeth, which can be pushed up against the rope when the the device is closed, but the teeth are oriented the wrong way, so they do nothing when the device is loaded correctly. What is this for? Even if the rope is loaded incorrectly, this auto-disengages the second one pulls a bit of rope through.

Seems like a protection in the case of incorrect rope loading - "anti rigging plate"?

https://www.youtube.com/watch?v=HgUNckR_ndE&t=370s    6:10 in this video

They do say it shouldn't be relied on...

Michael Mwrote:

Seems like a protection in the case of incorrect rope loading - "anti rigging plate"?

https://www.youtube.com/watch?v=HgUNckR_ndE&t=370s    6:10 in this video

They do say it shouldn't be relied on...

Yep, looks like this is the case. Its quite poorly designed, though. Difficult to have the rope engage it.

In order for it to function, it needs a decent amount of rope weight, or the user to be actively pulling down on the dead rope.

But, I guess it does its job as a backup for user error.