There were wide scale reports of authorities using chains and locks to seal individual dwellings on apartment buildings by chaining the metal gates closed. If you look at pictures from the field hospitals that they built you'll also note that there were metal grills on the windows as well. Although given what we are seeing here with people refusing to isolate and going out I don't necessarily blame them.
Everything I have read states they closed off certain doors to ensure that you couldn't get in / out of the building without getting a health screen.