In the test question with the magic beanstalks, the only accepted answer is Jack got off the magic bean stalk.
In three dictionaries that I have looked up (especially Le Robert & Collins), one of the meanings of decendre with etre is to 'climb down (a tree). Now the preposition 'from' is missing in those definitions but is that so significant a difference that the answer 'Jack climbed down the magic beanstalk" becomes incorrect.
