If you have a large starting capitalization value (billions of fiat dollars), any one of the participants who have seeded the system with their fiat will likely not effect the price in any particular direction when they withdraw or deposit (on the average). This is why you start out as a bailment provider prior to the float.
It's a one-to-one scenario. You give me a unit of fiat, I give you exactly one BCT token representing that fiat unit (for redemption purposes). Let the vault grow it's fiat reserves. When you hit the fiat reserve quota, you trigger the float (an IPO as an analogy) at which point your "shares" or BCT "scrip" is now floating freely.
What vault? Owned by who? Where?
If one person generates the coins and then sells them at a "1:1 ratio with fiat", isn't that just a fiat ponzi scam?
Another thing, probably just as relevant: the inflation rate for BTC is 33% for FY2012, or 4x the USD inflation rate (per shadowstats). At that rate it's honestly shocking that BCT trades for ~5 benny bucks as is. For FY2013, the inflation rate falls of a cliff to 12.5%, or only 1.5x the USD rate, and by 2017 it will be half the USD rate. If you're worried about the BTC being "too cheap", wait a year and see what happens.