[OJFord]

Post codes are sometimes totally unique for an address; they're always unique in combination with the street (or flat) number.

E.g. a short form address (useful for scribbling a return address on the back of an envelope/parcel for example) could be '123/AB4 5CD' instead of '123 St George Crescent // Upper Bockingbrook // Froimington // Froimingtonshire // AB4 5CD'.

[jjp]

Yep, many years ago had several thousand pieces of testing mail delivered. Names and address text had been scrubbed, but house number and post code was enough to get them delivered. All of the letters were watermarked Test, but somebody just put them through the envelope stuffer and out they went. Next test all the house numbers and post codes were changed to the bosses address!

[paledot]

I'd never thought of that. It would be technically feasible in Canada, but I'm not confident that a recipient or the postal service would recognize it as a complete address.