I wouldn't say they have to do anything drastic, but just make sure that they have a reasonable buffer. Individuals that are in those sorts of situations have many more options available to them when unforeseen life events occur. However, much of the ladder below them is fraught with people that would be ruined if even a delicate imbalance in their lives occurred.

Those are the types of people that need to watch their actions, and count their beans carefully. They're the ones I was speaking of specifically.