Is there a captcha, or can people ding-dong-ditch you from a continent apart?
Something like this really needs a periodic refresh or some proximity proof like NFC.
Who invented doors? Perhaps that’s where it all went wrong. /s
About a decade before that, we kids basically only had SMS text messaging, and it was very expensive in my country, mobile data doubly so. There was however a "please call me" feature, where you could send a "please call me" text to a friend free of charge. We used to send please call me's to one another all the time, not because we wanted to be called, it was just the cheapest form of digital communication.