An Aussie traveller has shared her surprise after spotting a mysterious code on her boarding pass.
Ruby, was preparing to fly from Brisbane International Airport to the United States when she noticed the four letters 'SSSS' printed on her ticket.
Posting to social media, Ruby, who now lives full-time in Chicago, said it was 'the four letters no traveller wants to see on their boarding pass'.
The code stands for 'Secondary Security Screening Selection', enforced by the US Transportation Security Administration (TSA) that flags certain passengers for additional checks before boarding.
Travellers marked with SSSS should brace for a more intense screening process than usual.
