Make it work along the same lines as a plug-in PowerBreaker-type RCD. Once the demand level falls, indicating that charging is complete (or the device has been put into standby mode – you would have to calibrate it first time round, I guess?), it triggers whatever mechanism breaks the power and changes the indicator from ON to OFF (turning off a low-power green LED in front of a retroreflective red background, turning a coloured filter wheel connected to the switch mechanism, etc).

Then to get it working again, you have to manually reset the switch, as the device is now itself completely unpowered. And it would work without all the complex jiggery pokery required to engineer something that can grip and push two smooth metal prongs out of itself… especially with the weight of some chargers’ wall warts… and without the risk of damage either to said wall warts themselves or whatever they should fall upon once ejected.

Heck it may need nothing more than a very simple alteration to a standard power breaker (which incorporates a full, failsafe-type, physical circuit breaker, a moving coloured indicator, and a manually-operated physical reset switch) – including even an in-wall power breaker twin socket (such as are installed around my workplace for plugging in cleaning and power tools). Just a circuit that taps off a tiny bit of current from the 110 / 230v feed, produces 3.3v DC from it, and runs a simple integrating ammeter connected to a low duty solid state relay that can bridge the live and neutral lines upstream of the RCD proper. As soon as that is triggered (by detecting a sharp, maintained fall in current – and therefore power demand), and before the short circuit can affect either the relay or the connected device, the RCD trips, cutting power to both the “vampire” charger and the trigger circuitry, reducing power drain to zero and leaving the electronics blanked and reset ready for the socket to be re-energised… Of course, it would have to be marked as no longer suitable for use as a normal circuit breaker, as this mod would probably compromise its efficacy… and it would be rather difficult to trace whether it tripped out as expected, or because of a genuine circuit fault.

The OFF Switch in any appliance.
Should actually be,an off switch ! A true disconnect to power.
A double pole switch built into any appliance,as a real disconnect switch. Your done.
The appliance AC switch circuit design is the culprit.
Everything is rocket science. “Common sense is expensive” !
Of coarse,the consumer will have to pay for that.

IMHO
A hint : If there is a light on when the appliance is “off”.
It’s still on.

BTW I’m not telling anyone to unplug they’re electric clock !
GOOD NIGHT ALL.
Cheers