Lyledunn,

The polarisation debate has been dealt with quite a bit on this thread:

https://www.electrical-contractor.net/ubb/Forum9/HTML/000167.html

A good example of a polarised socket which can only receive a polarised plug is the Australian/New Zealand example below.

[Linked Image from elkonv.com]

Like its American counterpart, it does not need an earthed (3 pin) plug to access the slots - the top two in the above example are live and neutral. You can see by their configuration that a 2 pin plug can only fit in one way up. i.e. it is polarised without reference to an earth pin. Two round (or square/oblong) pins/holes cannot achieve this.