The warnings do not have to be specific; for example, during World War II, Britain declared simply that it had mined the English Channel, North Sea and French coast.
Peringatan tersebut tidak harus detail; selama Perang Dunia II, Britania Raya menyatakan mereka telah menebarkan ranjau di Selat Inggris, Laut Utara dan pantai-pantai di Prancis.