Used them for years driving vans. Managers were red hot about it when it first started but eventually backed off when they realised you couldn’t win. We used to get pulled up for engine idling even though we had you keep them running when the freezer temps dropped if we were waiting about. Best one was the manager who kept on at us because we were revving too high before changing gear. Couldn’t get through to her the vans were automatics…In the end everybody just ignored it.