I'm sorry but this just is not true. As I stated before, if two people are swimming together and one starts to drown, the other will try to help. An UNTRAINED rescuer will be pulled under along with the victim. That is why there is special training on saving a drowning person.
Yep, that is how I was trained as well. The person drowning is in such a panic that they will use the rescuer as sort of a "step ladder" and the drowning victim is likely to push the rescuer underneath them, hence they both go under.