To walk up and do something like this...which would take a bit of effort....you’d really have to know the operation there. I don’t think it was the Nazis. I suspect it was disenchanted staff members taking out frustrations on the management.
Face it...what do you with a sign like this? You can’t show to anyone or the word gets out with the cops finding out. The logic of some Nazis stealing it for “show”...I find issues with.
To a hardcore history buff—a sick one without a conscience—it would be worth big, big money.