Singularity, sure, but I'm not even talking about that. I'm talking about current technology. How about giving homeland security blanket permission to track the location of everybody you don't like. Easily done using their phones.... You're a muslim/communist/dissenter and you choose not to carry your phone around? What do you have to hide? Also, how did you get on the shit list in the first place; you must have done SOMETHING...
If more than 3 of them end up in the same location, maybe send the FBI (or what the hell, the CIA) to "respectfully" check in on them... or hey, just record the conversation, while you already have access to their phones.
This is just one example, and no new tech is needed to implement it. Only an executive order, a friendly court, and some people willing to set it up.
I'm not saying this is what's going to happen; I'm just saying that in the worst case, everybody who knows how to do this will need to make a choice to either enable it or not. Sitting on the sidelines building cool shit and pretending it's both more important and irrelevant to current affairs is just not an option.