If it's actually the Vendor that is running the Group Buy (such as the Prestige GB handled by SunFly), then yes, this is how it could work.
If it's a member that is running the Group Buy, then often it is handled as a single transaction between provider and purchaser, who pays for everything and arranges for delivery of everything. Then, money is collected from the individuals when the order gets divided up and the full acquisition costs are known.
I'm less worried about being stiffed from a GB member than I am about putting a huge dent in my PayPal to the point where I lose the opportunity to purchase other chips for a while.