Bugging and GPS-tracking used to be so expensive that they were only used by governments and private investigators, but a quick Amazon search offers up a hidden car-tracking device for US$27 (£19). In the related items: a spy cam disguised as a USB charger, $52. These items are marketed as a “real-time teen-driving coach”, nanny cams or parental control software, but there is nothing to stop them being used for nefarious purposes. Meanwhile, law enforcement struggles to keep up: victims of stalking or online harassment are frequently told simply to stop going online, which for a 19-year-old in 2018 is like being told not to breathe air. As the National Stalking Helpline’s manager, Clare Elcombe Webber, points out, it feels like there are near-infinite technologies to help stalkers but few to help victims.