Let's get one thing straight here. If RippleLabs were to try and "Do anything they want" with the price of XRP as so many of you like to assert, I would be the happiest man on Earth. Why?
Because I would arbitrage the shit out of every single one of their trades and have the single biggest payday that I have or ever will have, in my life.
To top it off, the value of XRP probably wouldn't end up much different than it was originally.
In order to do "anything they want" with XRP, they would have to own a significant amount of every major currency with a strong market against XRP and simultaneously buy and sell these currencies with XRP in order to get the price to stick. But, they wouldn't want to do that because it would entail changing a significant portion of their XRP balance into another currency which in turn would make the XRP price manipulation less worth doing.
Price manipulation would cost them far more than it would ever earn them and they know it. They aren't stupid people.
They have enough XRP to buy out every ask on every asset. Not that I think they would, but they could. If they did, XRP would be worthless. How exactly are you going to "arbitrage the shit out of" that? Are you going to sell all your assets at the new high price for the worthless XRP?