My husband just reminded me what this actually is. It’s not for people being late for work, it’s for people demanding their money back from DB. And it’s only issued after the train was late for a certain time, an hour at least, iirc - because if they did this for shorter delays, they wouldn’t get around to doing anything but issue delay certificates. (Note that you only get the entire cost back when the train was delayed significantly, for several hours, otherwise it’s a partial refund at best.)