I've stayed out of this up until now, mainly because it has nothing to do with "outside" of American politics, and I have no clue how your country is run.
BUT ....
They are just like any other two teenage girls out for a fun time, it's just that they happen to be the Presidents Daughters. I feel sorry for them that they are constantly followed and expected to fuck up. Yes the have done something illegal, but what about Jane Doe from Chicago? She hasn't been caught because there are no camera's around her waiting for her to fuck up.
I think we're all guilty of having a drink under age, I know I am.
Although I don't agree and never will agree to drink driving, if they wanna do this, be discreet, and do it where they won't get caught, and for god's sake, get a lift home.
But all in all they are just like any two "unknown" teenage girls.