"Surely it was very unlikely that the money would be paid on a mere threat?"

Often the mere threat of such sanctions is enough to keep people quiet.

The mere threat of oil reductions can raise gas prices.

Although I'm at a loss to figure out how you can force them to give in by mere threats.

The mere threat of his anger is enough to ensure that.

Some towns are finding the mere threat of enforcement is enough to get the job done.

The mere threat of such a terrible weapon was perhaps its greatest power.

In fact, his type went into shock at the mere threat of extreme danger.

Usually the mere threat of the shock was enough to stop trouble.

Often the mere threat of winding up or bankruptcy is very effective.