In a lower reply of mine, I still have to ask why this is the case. If it's that big of a thing, then there should be rules defined to catch things. We have exception handlers for code and steps that go awry, why not the same for money, so the rest of the money flow can keep going, and only the weird things need to be checked out (and further rules then be refined).
That's what happens. Almost all transactions are Straight Through Processed. It's only when things go wrong (or very exceptional cases) that a human gets involved.
The banks can't afford for humans to be involved in too many transactions.
