What exactly do you mean by non-violent? Law enforcement is charged with the task of upholding laws and ordinances so that normal society can continue to operate peacefully. They sometimes ask "non-violent" civilians questions regarding a dispute or crime that took place. Is this considered interrogation? How about during a murder case where law enforcement is trying to piece together evidence and must "interrogate" someone that was not directly attached to the murder crime, but was simply a witness to it either by direct sight or by word of mouth. This individual in my mind should be investigated, which I interpret to being analogous with interrogation even though they are "non-violent."
If we let the police have more brutal means of punishment or ability to interfer with our life style as a whole we would lose our rights as a person.
However if the civilian is acting in a way that causes concern then yes they should but they need to know first the situation first.
Weeding through as many civilians as you can is an attempt of Little Stick Determined punishment, which obviously cannot happen in its entirety. It is a harassment and unconstitutional to require anything from a civilian that has not definitively committed a crime- remember: innocent until proven guilty. All interrogations of non violent civilians should be consented by the civilian.
In the constitution, unreasonable search and seisure is illegal. Plus if those who are not committing any violent crimes or just common civilians fear the police just leads to tyranny. And thats what we are turning into, with constant Government terrorizing the people with all these severe penalties for petty crimes. I cant remember who said this, but when the people fear the Government, tyranny ensues. And how much do we have to sacrifice just to avoid penalty? Such a state says that the people are no more than government slaves.