Automatic or blonde problem?

Hello SLK municipality. My wife drove with her SLK 200, 5 years old today, to a wash road system. The procedure is: Automatic on N, start engine and get off. When she just wanted to get in after the washing process, the car rolled off and drove against a mast. The damage is considerable, but my wife was fortunately not overrun by her own car. She is sure that the selector lever stood on N. Moreover, one employee told her “the selector on top of N, oh, you’ve already done that.” Question: has any of you experienced a similar situation?