What about NSA spying?

In briefest summary, we have learned that the NSA is collecting and saving information about every phone call in the US.  One assumes they are analyzing this as well, that they are creating graphs of who talks with whom and how much.  Presumably on demand they can go back and see who you were talking to at a certain time, and find accomplices to various activities they discover by doing so.

Yes I actually do have the same INITIAL reaction as everyone else, well almost anyway.  Pretty much, WTF?  But then my internal reverse engineer takes over and I ask myself questions like: 1) does this really matter?  2) Is this sort of thing inevitable with current technology (and therefore less worth tilting against)?  3) Is it really so bad, or is there something very much like what is going on that would not be really so bad?

SO here is a thought I just had that prompted me to write this post now.  Suppose there was a telephone system which was programmed so that it only worked for "good" calls, but simply did not work for calls that involved plotting or planning illegal violence.  And it did this automatically, no human intervention.  When you called your girlfriend to talk about her shopping trip it worked, when you called her to threaten her because you think she was paying too much attention to your brother it would not work.  When you called Walmart to get a price on a gun for self-protection it would work, but when you called them to ask about the price of a gun you wanted to commit armed robbery, it would not work.  When you called about flight school because you wanted to be a pilot, it would work, but when you called to learn how to take off, but did not need to learn to land, it would not work.

OK, such a system might be difficult to implement, but SOME of you are  already thinking of ideas about how you would approach this.  But this post is not about a new technology, it is about what we think of this feature set, good idea or bad idea?

As I have described it, it seems like a GREAT feature set to me.  A tool that can only be used for good.  No other human issues.