[gramie]

The issue comes when there are multiple people using the kitchen. Sometimes my wife runs the dishwasher when I'm not around, or vice versa. We usually rinse our dishes, so there is not always a lot of visible evidence.

The problem is when you have a dirty dish and assume that the dishwasher contents are dirty too (because usually we unload the dishwasher soon after it finishes). Then you put a dirty dish in, possibly making other dishes dirty. So you have to either hand-wash several dishes or re-wash the entire load.

[Dusseldorf]

Our dishwasher keeps its little screen on and blinking until you actually hit the on/off button, and we effectively use that as a cleanness indicator. We only turn it off after having cleaned out the dishwasher. So the off state always means dirty. On and full = clean, on and mostly empty = someone probably forgot to turn it off, easy to spot check.