Actually it is not what we're talking about, because they're not blind, they can use usual means of inquiry, and the technology. How comes already there are no firearm firing sound detectors, or remote-controlled drones with tasers in major streets to react instantly, ect...? There are ways to act which don't strip citizens from their power, as information nowadays is power.
A handful of people died because they lacked this power, and this will always be the case that people will die because of their lack of power, no matter what they have.
At the end of the day, there is 7 billions people, and only one world, one humanity, one future, so protecting the people from the government is more important than protecting the people from the people, at least as long as it stays manageable.
Every month, the world gets more peaceful, and more educated, we just didn't always have the internet flashlight. Making such a backdoor, it's another leak to oligarchy, because security and corporations can ally and spy the rest into uncompetitiveness. Ect... I will worry when I see blood on the street.