> in that particular instance they were only welding the back door.

It happened more than once.

Uploaded 2022-01-06: Xi’an. Clearly a front door. https://www.reddit.com/r/PublicFreakout/comments/rxddgp/chin...

Uploaded 2022-05-03: Residents locked inside homes with wires and bolts due to Covid-19 https://www.youtube.com/watch?v=mpfKZVTSp3I

Uploaded 2022-05-06: Shanghai https://www.reddit.com/r/oddlyterrifying/comments/ujoj33/in_...

Uploaded 2022-11-30: Unidentified city; worker shown welding a back entrance shut. https://www.reddit.com/r/CrazyFuckingVideos/comments/z8fpzy/...