In criminal cases. In civil suits someone always loses, so an average person cannot win more than 50% of cases.

As long as you don’t use them, sure. They are composed of basic parts, just well adjusted to the purpose. But if you do decide do use them, be aware that you cannot interfere with any radio communications in any way and/or destroy someone’s property. Which does not mean I am against shooting down someone’s drone on your property that is spying you, it’s just not really legal per se.