Hopper - Unlimited Items

If I put a hopper on a second one and throw an item (e.g. a Diamond Ore) on the border of the first hopper (which directs the item in the second hopper), the item won't disappear in the hopper, it will stay on the border and the chest fills with the item (until the item disappears after a few minutes).
Exploiters could make unlimited items!
See the screenshots for an example.