alt Hacker NewsI'm German and in the rare instance I eat out in an actual restaurant, I still do that "rounding up" if I've been happy with the service. Cash or card is not really an important factor for that scenario.
Let's say the bill says someting between 67€ - 72€, I would round that up to 80€.
Or sometimes (not every time though) when I'm getting a Döner kebab and it's ~7.50€ I'll round that up to the next full €.
The secret for Döner is to tell the Dönermann beforehand that you'll tip, then it usually results in a bunch of extra meat!