One I always enjoyed that's not on the list (because it's UK specific, I guess) is:

Buildings don't have multiple postcodes in different outcodes ( https://en.wikipedia.org/wiki/Postcodes_in_the_United_Kingdo... ).

Counter example:

* Merchant Venturers building, Woodland Road, Bristol BS8 1UB

* Merchant Venturers building, Park Row, Bristol BS1 5UB