The discovery that Barren Walkers were capable of teleporting between planets throughout the East Rim Consortium was made inadvertently, when a gang of youths cornered one and took it in turns to secrete themselves inside for the chance to roll around while it was pushed by the wind (ignoring the law stating that all Walkers were to be turned over to a Union official for analysis). When the teenagers reported that the Walker had "just disappeared" with one of their number inside, it was naturally assumed that they were lying, and they were convicted of the murder of their missing friend and sentenced to life. However, 6.8 Terran years later, another Walker was captured on Dabiel - just over 6.7 light years away - containing a skeleton later identified as that of the missing teenager.
Subsequent research revealed that Barren Walkers were capable of teleporting at the speed of light between any of the settled planets in the East Rim (though not, apparently, to any of the more venerably established planets outside it), but only when they were moving freely in the wind and their membranes enclosed a sentient being. Since no way of controlling this teleportation was ever discovered, for some time it was seen as an interesting but useless relic of, presumably, a previous galactic civilisation. By the height of the Orbital Wars, however, when many of the planets in the Rim found themselves with no allies and many enemies, it became common practice to place convicted criminals inside a captured Walker along with a store of the most destructive weapons currently available, and leave them both to be rolled to whatever planet (inevitably hostile, since they all were) fate settled on, where the weapons would be activated by a Gravity Re-Entry Field.