Great thread...and a very good issue raised...!!!
Cheers Ovid..
The problem I think is ...
1. That is too much on the same line.
2. And as its already been pointed out that anyone would read the code L to R...
The line looks like its been written to test someone's analytical ability rather than being easily readable and hence maintanable..
And I think thats more because of the 2nd problem...the second condition to be evaluated preceeds the first one in L to R order...
I guess the samething can be written in one line as below:

my $country = $card->country;
$country = ($country) ? ( ($country eq 'gbr') ? '' : uc "[$country]" )
+ : $country;
[download]

i think this is more readable....but agree with others that would be better to split this out..!!!!