A Pakistan soldier at the Pakistan-India border saw an Indian always took a bike, carrying a big bag, crossing the border.

First day, same person with the same thing happened.
Second day, Third day, fourth day, same thing happened.

On the fifth day the soldier thought that there must be something that the Indian is stealing.

So he stopped the Indian and checked the bag, poured out everything, found nothing but the sand.

So he let go the Indian and the same thing happened for the rest of the month.

The next month the soldier got the news: "We've lost 30 motorbikes in Pakistan!!!!!"