This technology is incredibly old, and definitely has already been abused. This just puts it into your hands. There's no sense complaining - anyone motivated or evil enough was already in possession of this.
That is a weird way to see it, just because a technology already exists (from the best I can tell the ability to identify specific people is a unique part of this) doesn't mean that we could be looking at an improvement to the technology or worry about it being put in more consumer technology making it easier for average people to use it.
How old are we talking?
I believe I experimented with this 6 years or so ago, then I found out other people did it way better than me. If you're talking about passive radar, it's really old. I don't know. Decades.