Wow, why would someone actually pay 30% more while there are still some high orders available to be sold at lower prices (even if a pump takes place) which would not equate it to 30% above?
How many exchanges are there that currently have 50k bitcoins for sale at a fixed price? If you bought 1k bitcoins from any exchange, it would be EXTREMELY unlikely that the orders on that exchange will still be in the same price range. I just checked Cryptsy, yes a small exchange, but there isn't even 20 bitcoins available for sale there and if all those sold, the price would be pumped to 300. Buying all those coins you're already seeing a increase is 22%. There is no way 50k bitcoins WILL sell and still keep each bitcoin under $338 a piece.
Do you also realise how many dollars you need to buy 50k bitcoins? $13.3 million USD @ $266 a piece.
So you are basically saying that the only reason one shall buy bitcoin from auctions like that is to buy large sum at once without manipulation bitcoin price? It may the case. But I find it easier to buy bitcoin from various exchanges in small packs say - less than 1k btc at once.
Far too risky. 1k at a time from various exchanges is still going to be 50 transactions spread across multiple exchanges. Again back to the 50k quantity bitcoin, if someone did have the capacity to buy it all at once, what would you need to say to this person to convince them that A; their details are safe with you, B; their dollars are safe with you and C; they are guaranteed to receive their 50k btc. This 30% figure being thrown around could be a security the client is willing to pay to ensure a 100% safe, true, legitimate sale of the bitcoin.
Someone else said "its an auction, its meant to sell under". Not true. I've been to private auctions, things like computers, furniture, TV etc sell cheap. Things like gold, jewelry and other items which are of true high value will generally sell quite close to their value. Some jewelry I've seen has been oversold in value simply because of what it is.