Although this looks very blatant, our cops, District Attorneys, FBI, and justice system do the exact same thing.
When "white collar" criminals are brought to courthouses, the cops know these guys are not going to pull a shank out of their trousers and knife them like some gang banger punk. But, they make them do the "perp walk" before the cameras as well. Some of the Enron executives (who were later never convicted) drove to the courthouse in a van free of handcuffs, but it stopped a couple of blocks of the cameras and media camped out there, put handcuffs on all of them, and then opened the doors to haul them out right in front of the reporters.
So, while the Peruvians were very blatant about it, we do the same thing.