There are two major ways in which you would not identify this flow of money:

1) You do a bad job at the due diligence and do not review anything beyond the income statement and top-level balance sheet accounts.

2) You turn a blind eye to it because it is favourable to you. Favourable can also be just the outcome of assessing the risk of 'cost of reversing fund diversion practices' vs. 'letting it slide because those diversions yield returns'.