That app is open source, you can check the code... It's actually less "invasive" than apps like Facebook and the like.

Other than that, there are already available technologies to track your phones/you far more viable and easy to use by the police and governments than what someone could achieve with this app (like sting rays, for example). And there are probably others that you don't know about that the CSIS uses, so I don't know why they would make something public to "trick you" to install it and then use it against you when they can just use technologies you don't even know about.