Forgetting to take the crab out is not a legitimate technique. This is just taught because it is harder to do it right.
Yes, the palne will take considerate amounts of sideload without breaking, but that don't make it right to land with sideload. Any person who has ever sat in the back of an airliner that lands sideways will tell you what a crap experience it is to land crabbed.
Just like you can do a roll with your feet flat on the floor, that don't make it right. Some airplanes will cover it up better than others, that's all.
