Escrow? What's that?

You can find a comprehensive definition here, but essentially an escrow is a trusted third party that mediates transactions.  In this case, when we begin to collect pledges, we will not ask you to transfer money to us directly;  Instead we will be using an escrow account with a widely-known financial institution, such as a bank.  The terms of the escrow will be that we will only receive funds if a certain percentage of the total pledged, say eighty percent, is actually paid.  Otherwise, contributions will be returned to their donors.  This mitigates the risk of donations being collected but the total budget still being too small.