We really do need some process where by the accounts of large companies are reconciled with reality. I understand completely that this is not possible for all the numbers investors want to see (Profit is made up after all). But there should be a requirement to report certain hard numbers (cash revenues and cash held for instance) that should be audited and correct to the penny on a given day. If a business claims to have received 1m $/£/E in cash sales, they should be able to show their accountant credit transactions for that amount and 0.1% of those should be checked by calling the customer and confirming they paid the money. The same applies for cash on hand on a historic day.

Nothing will make fraud impossible, but right now it's just so easy...