This is a very clever racketeering scheme. First, municipalities install parking machines that have only two options: cash, or pay using the app. Since very few people nowdays carry cash this forces the drivers to use the app. The app allowes you to pay only for up to 2 hours with an option to extend. Except, this option is always disabled, forcing a user to start a new session. Naturally, people want to avoid fines and they will want to pay ahead of the expiry time, hence paying twice.