John Locke and Alpert's test...

When Richard came to test very young Locke (S4E11) Alpert was angry when John picked out the knife, telling him that he had failed the test.

All those test objects mean something, I'm sure. What if the knife belonged to the one that would kill Jacob or cause his death, and that actually John chose correctly? I know Ben put the knife in, but he was manoeuvred into this by "John" possessed by Jacob's enemy.

At the very least John should've been marked out as someone to keep a very close eye on, a probable (albeit unintentional) danger, and I think Richard Alpert really missed a trick here.