Due to the advancement of GPS systems in today's world, the ability to use spy gadgets is really on the rise. Whether or not people are actually taking advantage of this is up for debate, but the bottom line is that the technology is there for anyone who wants to make use of it. For example, it is fairly cheap and easy to affix a GPS bug on the underside of a car these days and be able to track a person's vehicle all over the country without any problems, all in real time.
What is amazing is not so much that we can do this, what is amazing is that you can do this for less than a hundred dollars with no skills or training whatsoever. The barrier to entry has been removed due to advancements in technology and falling prices. A gps unit that used to cost hundreds of dollars can now be purchased for very cheap. Sophisticated computer programs to allow this tracking and display it on screen in real time has also become cheaper as well.
The miniaturization of cameras and audio recording devices has also led to the same effect among this type of spy gadget. With the advent of cell phone cameras and now cell phone video cameras, there are enormous amounts of very miniature cameras being mass produced these days so that they can fit into millions of these cell phones. All of these recording devices are super small and can be used for covert surveillance.
This is actually already a problem as many people can shoot live video and record audio using their cell phone while the cell phone is still in their pocket and only the lens can be seen through a small hole in the shirt. This type of setup is causing problems for some venues where audio and video recording is not supposed to be allowed, but because of advancing technology, it is difficult to keep it out.