My girlfriend left a cable hanging out of the front of the playstation, I came home to find the robovac hanging vertically halfway to the shelf having consumed the usb cable and started climbing up.
Don't have an Alexa so can't comment on how easy it is to trigger, although I don't know any Alexes so it'd unlikely be a problem for me.
What I can say about the google equivelent is that I find saying 'Hey Google' everytime I want it to do something is a bit of a mouthful especially if you want to do several things is shortish succession.
And my other problem is that I apprently say 'OK Cool' too often when I'm on the desk phone at work as my google account is full of recordings of bits of my work phone convo's where I've triggered it unwittingly.
"It's something that would have been unimaginable to happen in the UK a few years ago"
You say that but we had it happen in 1997 to prevent parliamentary discussion of the cash for questions scandal that ultimately toppled the Major Conservative government.
I believe that the Blair government considered it in the run up to the Iraq war too but didn't.
It's the kind of thing that'd make you reject purchasing it if only you'd thought to have tested that specific bit of it before buying it.