And that's enough, to make your life a living hell for a certain amount of time (be it brief or long, doesn't matter).
You know this from first-hand experience or from anecdotes and hear-say?
I've had dealings with police, courts and lawyers, both professionally and privately, on both sides (though not very often as defendant). In all my life there was one event that was really stressful and that was professionally.
Maybe we life in different countries or societies, but by and large, I've not seen this "ruin your life" part actually happen in cases on the level of "they ask you if they can check your phone". They happen, but mostly in the "they break down your door and arrest you for child porn" cases. Yeah, innocent people have been convicted of the highest crimes, and that does ruin your life. That is living hell, not having to deal with the justice system over some phone records.
Again, maybe we have different experiences and backgrounds, but most of the times I've dealt with police and judges, they were professional and while the results were not always what I wanted them to be, I cannot seriously complain about their behaviour. Maybe I've just been lucky, or maybe my own behaviour influences what I get back, or maybe the USA really has become this horrible police state.
Personal experience: I was stopped because I was on a bike on a sidewalk at 4 AM, the reason I was went there was to avoid getting hit by the same police car, they found a Swiss army knife on me I got fined $300, and accused/threatened with all sort of things so that I would feel lucky to get of with just a fine. I went to court and I won - I didn't get back my knife though, they LOST it-, it was a waist of my time, theirs and the judge's. But that's irrelevant). The premise is : if you look hard enough, you'll find something (bogus may be, but still). From a probabilistic stand point, what I described is bound to happen, question is when! I not saying all cops are like that, some are nice, approachable and reasonable (anecdote: few nights before the incident, in the same neighborhood, a friend of mine cut his leg on a glass door, we hailed a cab to go to the hospital -5 minutes ride- he refused, a police patrol was there, they saw us and offered us lift to the hospital) , some are simply assholes with a power trip, you're bound to encounter one of those a some point in time.
Ruin your life may be an exaggeration on my part, but my point still stands, as it is still a hassle that CAN ruin your life!
The anecdote above was in Montreal/Canada. I lived once in Algeria and more often that not we were harassed by the police for the mere fact of being there (but they had an excuse : power with no accountability, and they didn't actually give a shit about what the law actually said).
To finish, we're all judgmental assholes occasionally (quick, reaction without all the facts, and there could be a lot of reasons behind that, good or bad is irrelevant to this discussion), the difference with a normal person and figure of authority (cop for example) is that the normal person doesn't have the authority to act on it! And the way the laws are written, is just a mine field!