Once a system has been implemented to spy on all messages for one purpose it is relatively trivial to extend it for other purposes. The potential for abuse is l

Once a system has been implemented to spy on all messages for one purpose it is relatively trivial to extend it for other purposes. The potential for abuse is limitless, but just one example would be the group in power spying on dissenters in order to find and neutralize them. This isn't a hypothetical outcome, many governments without strong privacy rights are doing exactly this right now.