But there is always one or two. But those devices simply wouldn’t work. Although it there any safety issue feeding a transformer with DC for an extended period of time?
I would never induce dc into any house wiring. Period.
And any dc circuits should have totally different sockets and plugs.
Safety first. What good is alternate methods if your place goes up in flames!
Old time motto. If you try it and it doesn’t work — STOP IT.
Never leave anything that doesn’t perform, connected.