They wouldn't have to match globally across their entire dataset. Check your messages before/after landing, maybe post something like "lol, guess I'm going to M

They wouldn't have to match globally across their entire dataset. Check your messages before/after landing, maybe post something like "lol, guess I'm going to Madrid". Governments know you flight and boarder activity, financial institutions would know your purchase history. You've just eliminated a large amount of possible faces.