A Coffeeshop's Weekends Without Wi-Fi
An easier solution would be to just have hourly changing codes
How exactly is that easier than turning off the WiFi router on weekends? Who's going to update the codes? Who's going to print up the six zillion little slips of paper with "this hour's code"? Who's going to set up the router to kick off 'expired' machines without interrupting legitimate users?
Besides, according to TFA "The staff doesn't want to have to enforce the cafe's unspoken policy of making a purchase to use the space (and the Wi-Fi)..."