Dumpster Diving for Moving Boxes

I helped a friend move the other day. Nobody likes moving, but it's just a part of life. People especially dislike moving because cardboard boxes are quite expensive to buy. To solve this problem I drive around the back of smaller sized stores, and collect the cardboard boxes out of dumpsters. Most places separate out their cardboard for recycling purposes. The boxes are usually broken down to fit in a dumpster, but are perfectly good once taped back together. Avoid Larger stores that might have trash compactors and use compressed card board bails. It might also be a good idea to avoid restaurants, or produce markets, unless you want your stuff smelling like food. I don't know the legal ramifications, but figure it is helping the world recycle, so it can be all bad.