If humans can't recognize intelligence, then we won't be able come up with some other test to recognize intelligence.
The concept itself that is presented is quite sound: If you cannot tell that it's not intelligent, how can you say that it is not?
I cannot think of a better test. The only weak point as I see it does not say anything one way or the other about intelligence that is fundamentally different from our own (for example: doesn't happen to use natural language).