Do not open before the train has stopped

In Dutch trains a little sticker above the door-opening buttons reminds you that you shouldn't open the doors before the train has stopped. In fact you cannot open the doors before the train has stopped, the open button does not function before that. In old trains doors could be opened whilst the train was moving, but those trains have been decommissioned in the 1990s. The stickers remain. Sometimes I think the Dutch Railways has ordered millions of those stickers and that is the reason why they are still used.