Not saying that landmines are paragons of ethical weapon systems, but they are making a kill decison without a human being in the loop. Based on nothing more than a pressure plate or trip wire.
If we had landmines that could differentiate between a tank and a school bus wouldn't that be a step forward?
"The ensuing Mine Ban Convention has been joined by three-quarters of the world’s countries. Since its inception more than a decade ago, it has led to a virtual halt in global production of anti-personnel mines, and a drastic reduction in their deployment. More than 40 million stockpiled mines have been destroyed, and assistance has been provided to survivors and populations living in the affected areas."
I think the ideas is nip this one in the bud before it gets there.
I think there is a big argument to be made for their ethicality over landmines: unlike landmines, they are easy to deactivate and can be made highly visible while remaining effective. I don't think this makes them ethical, but I do believe that we have to consider how that changes their potential uses. There's an argument that it's far safer if we have hard rules around certain areas - "Enter a 500m radius around this military base moving more than 5mph and you will be shot many times" - than if we have fuzzy ones around guards and schedules. Certainties are often better than including a fuzzy human in the loop, which is why electrical installers all put their own lock on the switch rather than assigning a coordinator.
Not deployed as far as the public knows.
It wouldn't exactly be hard to add a "shoot everything that comes near us" flag to the software for any existing naval CIWS
Landmine bans in particular are kind of ridiculous because of how easy it is to build and plant IED's.
They are more effective against the intended target.