I think this is pretty common. Some people bury the pots and then bring them inside for the winter. They prune off the roots that grow out of the pot every year.

This is very common. I have 17 trees in a container orchard in the back of my yard planted just this way. I bring these containers into the garage each winter to keep from having to protect them as well as to get a very good shot at a breba crop.

Doing this is not without challenges. I find that maintenance of the proper moisture in the containers require constant attention. Watering every day or every other day in the hot days of summer is required. Also, you need to make sure that the hole you dig for the container has good drainage. I have two trees that suffered over-watering with the recent tropical storm that came through. They are recovering now ... but they almost bought it. With the saturation of the soil, the holes for my containers filled with water. It was not until i saw leaves yellowing that i put 2-and-2 together an realized what was going on. I immediately pulled my containers from the holes to find each with 8" of standing water ... not good.

-Steve