I've read a lot about this from at least the United States perspective. The rocket wasn't launched from the United States, but the FAA requirements on flight termination is the ceasing of thrust and removing "energy" from the vehicle by rupturing tanks if they pose a danger. The primary thing that's trying to be prevented by flight termination systems is damage/danger to uninvolved parties. So if it's low to the ground simply shutting off the engines is a perfectly fine solution to the issue. If its higher then rupturing the tanks will be needed as it's likely going to land outside the safety area.