Financial futures such as index and Treasury contracts mostly use accountability levels rather than hard caps, because they are cash settled or have enormous deliverable supply and cannot be squeezed the way a crop can.
Crossing one is not a violation. It triggers an obligation to explain your position and strategy on request, and the exchange retains the power to freeze or reduce it.
Example: an index futures accountability level in the tens of thousands of contracts means a large macro fund may hold more, but must be prepared to justify it to exchange market regulation.
Related: position-limits, large-trader-reporting, hedge-exemption, cftc