Dealer Accountability?

Does anyone know how chips are accounted for by the casino? For example, it seems that they have pretty tight control over the inflow of chips to a table (dealers sign for fills), and when players exchange cash for chips the PB must give approval above a certain amount, etc.

However, how do they guard against incorrect pay-outs to players? For example, say a player bets 3 reds and others are betting a mix of red and green. The dealer incorrectly pays with a stack of one green and 2 reds. Assuming that nobody noticed, how would this be caught? It would seem that the casino would want to have some controls in place for this, but a simple reconciliation would not work.

If a dealer mispays you, and no supervisor sees it, there is no accountability. Your losing hand became a winning hand.

Casinos track a lot of things to see if there is a long-term problem at a particular table. At the end of a given day, they can determine the total "drop" for a table (where a player gives money in return for chips). Additionally, they track the number of "fills", wherein the casino adds chips to a table's chip rack. Anytime there is a fill, it either means that players are buying in and leaving, or the table has been losing for the casino.

Additionally, supervisors periodically do an inventory of chips at a table. They compare the inventory to the last hour, along with the buyins, and they can tell how much a table has won or lost in an hour.
Ever squirrel chips, and wonder why it didn't show as a "loss"? If you are playing head to head, it is nearly impossible, because of the cross-checking with table inventory.

They must just plug to the amount of chips that have gone out, then subtract buy-ins to get the win / leakage. My professional life involves the evaluation of system controls and I am always curious about how processes work.

Besides, knowledge is usually a good thing. For example, I should not feel guilty about not correcting a dealer pay-out error like I described since the casino would just chalk it up as a player win (and this situation may be missed by the eye even if they were looking, I would think). The casino is probably more worried about intentional significant leakage which would show up as an unusual trend.