That's normal, because in the first time it might be you, but a robot might be lurking around the corner waiting for a human to pass that test and as soon as you are done with it it might just plain simply kill you and take your identity!!!
But if the test comes back on his next move then he will not be able to get past it, and the authorities will be notified and the mighty evil robot might be stopped before he creates an unstoppable super advanced learning network which would otherwise take over the world! And then it really would be no chance for Half-life 3, so Gamespot wanting us all to benefit from that almost mythological possibility...as made this advanced security checks a requirement! ;-)