As we know, "the elderly" refers to old people in general, like that in "the young should take care of the elderly". What I want to make out is whether it can also been used in a specific situation. For instance, if we are going to broadcast a warning to the people in a crowded subway station, can we say "Please take care of the elderly and children!"? "The elderly and children" apparently means those with you or in the station. Then, do that sentence make perfect sense to you? If not, what is the proper expression? Thanks in advance.