I don't know if it is a standard, but I have seen them a fair bit (UK). I did say "additional", though. I mean, yes, you'd want to be able to locally isolate

I don't know if it is a standard, but I have seen them a fair bit (UK). I did say "additional", though. I mean, yes, you'd want to be able to locally isolate the power as well, where possible. But when the device is capable of running cordless, you're losing that scope.