This video is disturbing for those using landlines. If you know anybody with one, you should send them a link to this video.
https://www.youtube.com/watch?v=zP9VAyfj6iI
Hehe, this has been around for awhile. it used to be used for placing long distance calls overseas or collect.
POTS can take upwards of 7 seconds to disconnect the circuit. In the meantime, the line continues to receive power, and thus the call is still connected.
I know the feature has been around for a while but I think the scam is relatively new unless it used to be a thing and came back. In the comments someone said it was used so you could pick up the call in another room. But maybe that's just another use of it. And all that time, I left it off the hook when I moved. :D Maybe it's time for them to retire that feature. I'm sure there are better ways to do that now.