Captain America did this kind of thing all the time.
I had a buddy in my college gaming circle who was Hispanic and grew up in a not-too-great part of Hollywood. He was smart as a whip and the nicest guy in the world, but looked scuzzy. So he disappeared one day. At first we didn't think anything of it, assuming he had gone home to visit his mother and hadn't mentioned it. But that was kind of unusual--we were a pretty tight knit group, and generally knew each other's comings and goings. A day or two later one of us called his mom. He wasn't there. We started to get worried. One of the guys, a white guy with more street smarts than I would have guessed, had a hunch. He drove down to the sheriff's station and asked for our buddy. They had him in a cell. What was the charge? There was none. Could white guy take him home? Sure. No problem.
He had been picked up for being in too good a neighborhood for his physical appearance. It was obvious to me at the time that this was fucked up and grossly illegal, but I didn't understand what had happened. In my sadder but wiser old age I think that once the police actually talked to him they figured out that he wasn't some random gang banger. But at that point they had already crossed the line into illegal arrest on racial lines, and they didn't know what to do with him. My guess is that it was something of a relief when white guy college student came to pick him up.
He never really talked about the incident afterwards, and didn't pursue it. I can't blame him. He would have been opening himself for villification with little prospect of anything coming from it. There was a similar case around the same time of a black guy arrested in San Francisco for walking in a white neighborhood. It turned out that his father was a federal judge. He raised a stink afterwards, but his family gave him the social capital to make it stick. My buddy from a not-so-great neighborhood? Not so much.
When I hear white people deny that this sort of thing goes on, this tells me that they don't have any ethnic friends. They may think they do, but those are merely acquaintances at best.