- World Rugby boss hails Olympics effect
- Brett Gosper using sevens to tap new markets
- Spending $500M on game in 2009-16 cycle
- Also faces doping and concussion challenges
(CNN)At Heathrow Airport, a giant billboard shows model and actress Cara Delevingne, her fist raised, with a curious expression on her face and the slogan "Don't Crack Under Pressure" underneath.