They're simple plot devices to get the Doctor and companions where they need to be. That's all. Not really much in this episode outside the Ponds leaving. I expected the Statue of Liberty twist pretty much the second they revealed a non angel living statue.

whomod said: I generally don't like it when people decide to play by the rules against people who don't play by the rules.
It tends to put you immediately at a disadvantage and IMO is a sign of true weakness.
This is true both in politics and on the internet."

Our Friendly Neighborhood Ray-man said: "no, the doctor's right. besides, he has seniority."