You can buy a power strip with a two prong "figure 8" connector providing three grounded outlets. Try to sell that in a brick and mortar store, it would be closed, razed and the ground salted so they won't even try it next time.
Three-pin appliances require a ground to be safe. By using a power strip like this, you're creating an unsafe configuration with a high risk of electric shock if there's a fault with an appliance.
Also, the little figure-8 connectors can't pass a high amount of current safely, and lots of 3-pin appliances are relatively high draw. That's a fire risk.
I'm not sure who's responsible for the enforcement in the US.
I presume in the USA https://en.wikipedia.org/wiki/U.S._Consumer_Product_Safety_C... would get involved or the FDA.
Can you elaborate on this?
My MacBook charger has both a two-prong and a three-prong cable. Why would it be any more dangerous to plug my MacBook into this power strip using the three-prong cable than to connect it directly to the wall with the two-prong cable?
However, there is also this: http://i.imgur.com/ftPT7sC.png, which grounds from either sides or in the middle for sockets like these http://i.imgur.com/FnXMndC.png
The charger looks like this: https://support.apple.com/library/content/dam/edam/applecare...
And also comes with a longer, three-prong cable that replaces the little two-prong piece: http://www.ebay.ca/itm/like/172352962036?lpid=116&chn=ps
The grounding pin does have a use, though: some cheap powered USB devices will put out a voltage relative to ground on their '0v' lines. If you touch a MacBook that's plugged into one of these devices, you can get a small shock. If you're using a 3-pin adapter, this doesn't seem to happen.
I know that it offers no grounding, that's a risk I have no choice but to take on my equipment because my building is not grounded. So I'm not sure someone selling a strip like that would be fined if my landlord isn't even forced to ground the building.
* Replace the wiring with grounded cable. Expensive.
* Replace the outlet with a GFCI and label it "no equipment ground". Gives most of the safety benefits of a proper ground, and is up to code. Not that expensive.
* Use a cheater plug [1] and connect the external ground tab to a pipe or something else grounded.
What you're asking for is basically a cheater plug plus an ordinary power strip, sold as one integrated unit. Better to keep them separate so that people know what they're dealing with. Also, what the poster upthread was describing didn't have a grounding tab, so there was no way to hook it up safely.
(The landlord isn't required to set up grounded outlets out of a general principle that you only need to bring things up to code when you're modifying it, and that something that was legal at the time it was installed stays so. Your unit could legally have knob-and-tube wiring if it's old enough!)
So, it's likely that you have Line and Neutral connected, while Ground is "floating" (not connected). Which means that, if something goes wrong inside the appliance, it can be dangerous for other appliances, and more importantly for you, too.
Especially if there are exterior metal parts inside the appliance that are grounded and a wire is touching the metal from the inside, too.
Is it that plugging multiple 3-prong devices into one power strip would connect their grounds together, and if one has a short they all go hot?
Of course, lots of people mis-use them, and when they do they're unsafe. I assume they're still on sale because they have a safe and appropriate use.
EDIT: I, personally, would never have one of the linked adapters in my house, simply because the risk of someone being an idiot with it without realising is too great. (I also come from the UK, where our plug and socket designs are nothing less than straight up paranoid when it comes to safety, and the US electrical setup seems unnecessarily risky to me. At least it's lower voltage...)