It does not happen often, thankfully, but theoretically a source-drain short can happen on the mosfet that controls the extruder heater. In that case, currently thermal runaway protection can detect a fault, but not stop it.
I would welcome an addition where in these cases the power device (if configured) will turn the printer off.
In the future I would welcome manufacturers to add source-drain short detection in hardware, or just adding a relay to “unlock” the heater.
What are your thoughts?