The Rennik twins were the sons of Rennik, a spacer who owned the Worldhopper.
During the journey to Oradin, they strapped a conical scrap-metal cap that trailed a long ribbon of bright blue fabric on top of Gate, Wedge Antilles's astromech droid, and then used powered-down blasters to try to shoot the ribbon. Being poor shots, they settled to shooting the droid instead.
When Whistler, the astromech droid of Corran Horn, sliced into the Spaceport Security Authority and married a picture of a Twi'lek who was pursuing the droids into an arrest warrant template, the Rennik twins started scattering shots into the Twi'lek's direction, giving the droids the opportunity to escape.