للتوضيح أكثر بحثت و وجدت أن بعض الدول مثل بريطانيا و أمريكا و كندا ... بعتمدون على شركات الطيران أو الناقلين البحريين بتزيد الجمارك و أدارة الهجرة و الجوازات بنسخة من بيانات مغادرتك للبلاد

Some countries, including the UK, the US and Canada do not stamp your passport on exit. However, they still know you have left. If you leave by commercial means (such as air, train, etc.) the airline or train company will forward a record of your departure electronically to customs on your behalf. This cuts costs and speeds up the process.