same author as the shrinking band post above.

This one is for people afraid of heights: the victim's wrists are bound to a balloon large enough to carry their weight, which will reach neutral buoyancy maybe 500-1000 meters above the ground. The balloon is released to float away into the wind. A device will sever the prisoner's attachment to the balloon after some amount of time.

The prisoner has no way to save themself, their survival depends on whether or not someone on the ground spots them under the balloon, takes a helicopter up to them, and rescues them before they are released to fall to their death. For the reader's enjoyment, the prisoner is naked and gagged.