It’s a well-worn tactic in modern city sieges such as the post-Yugoslavia conflict. It doesn’t take that many troops to blockade a city, build fencing and barriers and maintain a few check points. Nothing gets out or in that isn’t approved and controlled. It was very effective at bleeding cities dry of all valuables, in effect looting as the residents went hungry. They brought the valuables to their besiegers.
In July, 1967 during the Detroit Riots I delivered campus mail every day for the Wayne State University mail service as a worker while attending WSU. My A&P grocery store totally burned out except for some light fixtures hanging by wires and some charred walls left over. A block from my cheap apt.
After the 2nd day of rioting we could volunteer to work, which I did.
They supplied a fully uniformed and armed National Guardsman to ride on the running board of the mail truck and to jump off to walk beside me. He held a rifle on a 45 degree angle and watched up (”I’m looking for snipers.”) He did encounter snipers and fired a couple of warning shots while I was in the truck getting package mail. Then all clear. Then we went on walking.
At that young age I thought it was exciting.