Google Geocoding : Flattened address needs to have a full country name

Hi,
I have had many cases where Google would not geocode a postal code/city/country combo.
It looks like it has some issues with country codes in the search query.

For example, if you look for PC:1000 City:Tunis Country:Tunisia
the string will contain something like
1000 Tunis tn

And I suspect this to not work because of some confusion with Tennessee.
Actually, it seems there is a Tunis near (or in ?) Memphis.

So the Geocoder has to translate country codes to country names before.
What do you think ?