To allow for training of the ML to differences of each users the authors describe have the end-user first play a game Unsuspecting user downloads “Evil Flappy”

To allow for training of the ML to differences of each users the authors describe have the end-user first play a game Unsuspecting user downloads “Evil Flappy”, an app where they have to tap on the screen mindlessly to advance some objective. During this tapping, the app uses transfer learning to tailor the model to the user and test its own predictive capacity. Very sneaky indeed...and I loved Evil Flappy :-)