Blackstone Group CEO and informal Trump advisor Steve Schwarzman said a lot of important things during an on-stage interview earlier this week at the CNBC Institutional Investor Delivering Alpha conference, including about Brexit and the presidential CEO council he once chaired. But Schwarzman's most surprising line was about what he claims to have never done:

Schwarzman also claims to have never used a mobile app, including ride-hail ones like Uber or Lyft.