A few trading firms have learned to have a second system that monitors transactions to keep tabs on profit and loss. If the things swing out of the expected range, it is time to have a human look at the situation. If things get really out of hand, it is time to rate limit transactions, or halt them out right. Sudden extreme profits usually indicates a data entry error on your system, not that the rest of the market has gotten really stupid.
Most inventory systems have a way to track cost of goods, age of inventory, and expected profit margin. Eventually retailers will start filling in those details, and tracking them, so they can notice when something goes expensively wrong.