In theory some rich Sheikh could buy up a ton of BTC and turn the economy to shit, just for the lols, and wouldn't even feel the dent in his pocket. Not likely though.
If he buy a ton of BTC then BTC price will skyrocket.
Let's HOPE someone do that, we will all become rich
It could be a problem if the market can't sustain the price after the big purchase; somthing like that could trigger a bubble and bust event i believe.