A Google engineer revealed that more than 90 percent of active Gmail accounts don’t use two-factor authentication (2FA), reports The Register. Given the low uptake, The Register asked Google software engineer Grzegorz Milka why 2FA isn’t mandatory for all Gmail accounts. Milka chalks it up to usability, adding that, “It’s about how many people would we drive out if we force them to use additional security.” The statistic was shared during a presentation at Usenix’s Enigma 2018 security conference in California.