The Canadian example is intersting in that it seems the deposit has to be high enough to make it work. In Germany it's 25 cent, which adds up quickly and is usually a nice bit off your shop.
The point about commercial businesses needing extra space - I don't know, they have space to store the full bottles, so they should be able to store the empties too - they take up the same space? But then I remembered that in Germany many drinks come in glass bottles, in sturdy cases, and are easily stackable. Also these bottles and cases have always carried a deposit, so people are used to returning and storing them. It's a bit different with flimsy plastic bottles and cans.