Steven Pinker describes how that went:
> "As a young teenager in proudly peaceable Canada during the romantic 1960s, I was a true believer in Bakunin's anarchism. I laughed off my parents' argument that if the government ever laid down its arms all hell would break loose. Our competing predictions were put to the test at 8:00 a.m. on October 7, 1969, when the Montreal police went on strike. By 11:20 am, the first bank was robbed. By noon, most of the downtown stores were closed because of looting. Within a few more hours, taxi drivers burned down the garage of a limousine service that competed with them for airport customers, a rooftop sniper killed a provincial police officer, rioters broke into several hotels and restaurants, and a doctor slew a burglar in his suburban home. By the end of the day, six banks had been robbed, a hundred shops had been looted, twelve fires had been set, forty carloads of storefront glass had been broken, and three million dollars in property damage had been inflicted, before city authorities had to call in the army and, of course, the Mounties to restore order. This decisive empirical test left my politics in tatters (and offered a foretaste of life as a scientist)."[16]
"Montreal was once known as the bank robbery capital of North America."
https://montrealgazette.com/news/local-news/history-through-...
NYPD went on strike in 2014, if anyone wants to research that themselves... RIP Eric Garner
Vox did an analysis of the NYPD "slowdown"[1] as it was also a useful natural experiment. They didn't enforce the low-level "broken windows" crimes, but only did the minimum required by their contract. Needless to say, the city fared far better than right now.
That said, neither of these is a good example of what life would be life without government-supplied police forces. They are very rapid, unplanned changes in policy which don't allow private parties to hire private industry replacements and don't reflect how much less tax would be paid (about 40% of local government revenues).
[1] https://www.vox.com/2015/1/6/7501953/nypd-mayor-arrests-unio...