Plenty of people. Skimming the news for "[x] people dead" and "[city name]" is not computationally expensive and the script only needs to run maybe twice a day.

Plenty of people. Skimming the news for "[x] people dead" and "[city name]" is not computationally expensive and the script only needs to run maybe twice a day. The infrastructure costs associated with running the service should be pocket change. All the users in the same city would be triggered by the same event. The service per user actually gets cheaper with the number of users. In fact nothing in the dead man switch is computationally expensive and all of it is event driven. Its basically just a database of (email, location, last_checked_in). Thousands of users would take up mere kilobytes of storage. You could run the entire thing severless and it would take years before it would even be worth billing you. I would totally pay $1 a year for this. Maybe more but probably not much more. With just a few hundred users, you'd be well into respectable side project money.