The fact that you can do even do this should highlight how bad the 110v American sockets are.
With the 220V UK style socket this never results in anything happening.
It is possible although maybe not with a penny - I live in the UK and when I was 6 I performed exactly the same experiment. The only difference is I had to stick something into the top hole to wedge open the shield, before I stuck a coathanger wire across the other two (which I did while holding it with a dry cloth thankfully). This resulted (at least in my memory) in a big flash and a lot of black soot on the socket.
But for a sufficiently determined and dumb child it is still perfectly possible to ram things into the UK socket and arc it, it is just a bit more tricky.
I wholly agree with you, although I think it's worth pointing out that the specific risk here (America's dangerous socket design) is purely incidental.
The underlying problem (Amazon appears to be naively scraping information from the information and automatically applying truth judgments to it) needs to be resolved.
I guess they wouldn't entirely eliminate this specific problem -- if you were determined to get a plug in halfway and touch one end with a penny, then you could probably pull it off -- but they do make unintentional errors of this variety much less likely.
I replaced all my receptacles with TR versions when I moved in to this house. It takes an afternoon, but it's a good opportunity to make sure they're wired correctly -- you may be surprised to learn that many won't be -- and to replace old, worn-out outlets that present hazards. It's a very easy job for a homeowner, given some basic knowledge about residential wiring that's easily obtained.
On 220uk plugs the part of the pins that is partially exposed as you insert the plug is insulted to prevent people doing stupid things like this coin thing.
But for a sufficiently determined and dumb child it is still perfectly possible to ram things into the UK socket and arc it, it is just a bit more tricky.