As unions bunkered down for a process of arbitration with Qantas, the airline faced a new PR disaster over a Twitter campaign. As part of its foray into social media marketing, Qantas put out an invitation on its Twitter feed for members of the public to sing its praises. Top tweets were promised a gift pack including a pair of Qantas pyjamas. But the competition was quickly flooded with a stream of angry and sarcastic comments, and people simply taking the opportunity to have a joke at the airline's expense. ''What's odder, the idiotic timing or the imbecilic prize?'' asked one tweeter. ''Alan Joyce now seeking an injunction to ground twitter due to QantasLuxury fiasco,'' tweeted another.