Ranger REG
Explorer
Well, it's true they should have run some kind of diagnostic, but when they activated B4, he is found to be primitive by Data's standard.ninthcouncil said:
The other thing that really stank was the whole downloading Data's memory into B4 thing.
"Why are we doing this, Geordi?"
"It's necessary for the subsequent plot, Commander Riker, that we do something extremely stupid and utterly useless, like filling an obviously planted android with high security StarFleet knowledge. I'm sorry, but that's the best explnation I can give."
"What's this thing on the back of B4's head, Geordi?"
"It's a plot device, Commander. Now go away before you make me act sensibly."
Then again, when Data was activated, I'm sure the Federation have ran all kind of diagnostics and probes, and find him to nothing wrong with him ... and yet, he has a deeply imbedded program that allowed him to look for his creator, Dr. Soong, if he is within close range. You did remember that episode, right?
So it is not so much about B4 that concerns me, it's Data himself. Last we saw him, he has an emotion chip installed. He hasn't made use for it, to the point of denying it ever existed in this movie. Correct me if I'm wrong.