When the iconic US snack brand Cracker Jack decided to replace its "prize" with a QR code, it felt ominous. Instead of finding a tiny baseball card or a temporary tattoo, kids are now directed to a mobile game, which lets them share a baseball-themed picture of themselves with the Cracker Jack logo with their friends on social media. R.I.P, all that is pure. Will it ever be possible to shield kids from being tracked, analysed and bombarded with advertising - and used as advertising - if we can't do so with a classic snack?