I have been telling Mrs. C for quite some time that the purpose of most of these types of shows is twofold, to titillate the sense of enjoying someone else's scandal, and to make oneself feel normal by comparison.
Your analogy is interesting, and I would take it a step further. More "dramatic" oriented reality shows, mostly having to deal with LEOs (The First 48, Live PD, and the Pac-Man era example, COPS), are the contemporary equivalent of Londoners in the 1700s going to the gallows with their picnic lunches on a Sunday afternoon to see the hangings or pickpocketers, all the while having not-yet-hung pickpocketers "working" the crowd. And the reason for the crime was the same, in terms of the era's technology: in the 1700s it was gin, while today it's meth, crack, and horse.
First of all, people, in England, turned out to watch hangings, beheadings, and such ( don't forget the whole people in stocks...there, in Bermuda, and in Colonial America...in later eras ) for several different reasons. One was to teach their children to NOT commit crimes, another was to see the guilty get what was coming to them, and some, probably just took some kind of pleasure from viewing these acts.
Secondly, such viewings went one hundreds of years PRIOR to the 1700s, as well.
Now...as far as pick pockets go...child pickpocket gangs weren't anything "new" when Dickens wrote OLIVER TWIST. Pickpockets of EVERY era, gin or no gin, went where the people congregated. There are even extant records of pickpockets roaming through the crowds, who massed to watch PASSION PLAYS, at Easter time, in the Middle Ages.
But you ARE on the right track.