I think as a general rule the idea that you give someone something that they are unlikely to solve because they are not completely familiar with the problem space does measure some things well - specifically, how one performs with something new and unknown (a critical programming skill) and their ability to abstractly reason as opposed to having memorized some information.

Although for other things related to the job not that useful.

That said I was talking about your comment that it was somewhat unethical; they didn't so much think that they gamed the system but that the system was so inefficient at doing what it should do that someone had to fit themselves to the system to get in.