India, July 3 -- A prank that surfaced in a handful of viral videos this week has spread rapidly across Indian social media, with a growing number of people filming themselves approaching e-rickshaws and switching them off mid-journey using a smartphone app - stranding people in traffic and racking up millions of views on Instagram, YouTube, Reddit and X.

The apps involved, BAT-BMS and Lossigy, exploit a gap common to unsecured lithium-ion battery packs sold in India: Battery Management Systems that connect over Bluetooth with no password protection, turning any nearby smartphone into a kill switch of sorts.

In a test conducted with a driver's permission, HT downloaded Lossigy from the Google Play Store, located a nearby e-rickshaw, and...