Some times the items pass through without a problem but more often the dog's life is at risk. They either need surgery to remove the object or the need treatment to support them due to diarrhoea/vomiting and abdominal pain.
My point is train your dog not to eat items found however small. You can try using bitterspray, unrelentless training or simply distraction using treats/toys.
It is wise to keep a supply of soda crystals in the house. These can be used to make your dog sick if something is eaten - although you should never do this if the item is caustic/sharp. Check with your vet with a quick phonecall if you are unsure. By making the dog sick as soon as the item is eaten could save his or he life. It is sad to see the suffering caused by a labs greed - just be aware of the problem ok guys.