I genuinely think this point has long since come and gone. Most encounters with police are going to end fine, but there's basically no recourse in the majority of cases where they don't.
The situation is that American police are generally there to enforce the law, generally follow policy but, depending on area, are infested with a minority of types who use or threaten violence whenever it makes their job easier or simply serves their ego. And these forces also tend to have a much larger group who won't say anything about the overt criminals - out of conformity, alienation from civilians or because the intimidation factor is convenient to them. This situation, that is effectively well publicized at this point, fundamentally changes the way police and civilians relation because it goes a lot of police actions a threatening quality and so, as I said earlier, it's hard to have question appear "optional" to the average person stopped by the police.
But that just brings me back to my point about the framing of this article. If The Guardian believes this question is problematic --- and I agree with them, if they do --- they should write an article about how you don't have to tell the police anything about your Twitter account just because they've stopped you on the street.