Why not just get one of those wi-fi setups where a wi-fi password is printed on the receipt and the number of minutes/hours of wi-fi the customer receives is ei

Why not just get one of those wi-fi setups where a wi-fi password is printed on the receipt and the number of minutes/hours of wi-fi the customer receives is either a fixed amount or tied to the amount of margin you're making on a customer for that transaction. It basically says to the customer "Want to continue working here? Buy another coffee." This of course doesn't address those that show up with their personal hotspots, but I feel like that is still the minority of coffee shop campers. Removing wall outlets is another deterrent. You can only keep working as long as you have juice. That said, battery life for mobile devices is getting longer, so this tactic isn't always effective.