Don't those adaptors have only two wires in and two out? Nothing strange at all then, huh?
But one of your colleagues here mentioned, that some products in USA come with an adaptor, which allows you to plug threewire (separate earth) device into two wire installation. Which is wrong, in EU it is forbidden. Any of our inspection technician would likely want to kill ya, If he would see you doing such a thing.
Summary: In EU, there is no way you can plug a device with threee wires (Class I, L N PE) to a two wire socket.
Threewire EU plug simply does not fit into two wire socket (we have almost none twowire sockets, 99% of them are like german Schuko type, finding a socket for 3w plug is not a problem at all). And any power adaptors from 2 to 3 wires are forbidden, illegal and brutal safety risk.
On the other hand, 3 to 2 wires adaptors exist. The 2w plug fits into 3w, but these 3-to-2 adaptors are made with more than one output sockets. They allow you to connect more 2w (Class II) devices into 3w socket. Which is right, because 2w (Class II) device are made safer than safe, they don't need to be earthed.
See? The 2w plug fits there:
http://i3.cn.cz/1131518818_zasuvka.jpgBut here you just can't fit the 3w plug. Impossible. Simply no way. Any attempt of that is illegal and safety risk.
http://www.elektrahk.cz/gif/e030200.gifOr did I understood the american adaptors wrongly? I think that it is obvious, why trying to plug 3w device into 2w socket is a safety risk.
It is a little more complicated, it would be a nice discussion, but it doesn't fit here, I don't like making mess in threads :-)