To be clear, there are humans involved if the amounts are large enough - if you're playing with stocks and margin in your brokerage account it'll probably liquidate automatically, but even when I got a "margin call" by accident they gave me three days to resolve it before liquidation would happen.
Part of it depends on what the margin is used for - margin for VTX is going to be handled differently than forex margin.
Part of it depends on what the margin is used for - margin for VTX is going to be handled differently than forex margin.