Well, the idea is that anything and everything can be hacked. It’s just that the difficulty varies wildly; some being trivial whereas others are impossible until someone finds an exploit. If you’re working with a total black box, you’ll have to make many assumptions, which means that figuring stuff out may take a while. If there’s at least some documentation, such as a patent, you won’t have to guess absolutely everything. That doesn’t guarantee that it’s going to be easy. Maybe the patent doesn’t go into much technical detail, but still manages to describe the product in just enough legal detail that the company can sue anyone trying to come too close.