It's a social thing. When you know the service might be down when you need it at the last moment, you just plan and do things quite some time before the deadline so you don't get caught.

In the twenties century, trains in Spain where completely unreliable: they could leave one hour early, or 3 hours late, yet people would get fired if they couldn't get to work in time. But it still worked: people just didn't run into the train station 5 minutes before departure.