As I understand the convention is to put brackets around the country code (http://www.businesswritingblog.com/business_writing/2007/01/how_to_forma...)
The formatting is handled by the 3rd party libphonenumber code, which provides a few different options for formatting. If you're not seeing parenthesis for the country you're using, then I'd assume that is by design.
Also, the article you've linked, talks about formatting the area code, not the country code, and in general, I've only ever seen parenthesis used for area codes.
Thanks cdale, just to highlight, here is the country stuff from the article
"For international numbers with country and city codes, Microsoft uses one set of parentheses around the country code followed by a second set enclosing the city code, like these codes for London, England: (44) (71). These numbers in parentheses are followed by the local number rendered in the style used by the particular country."
hmm, I've honestly never seen that format used. Then again, I don't use Microsoft products, so that might be why though this kind of thing is very subjective I find.
I'm not sure if we want to add in an option to support this kind of formatting. My initial thought is not, unless upstream does it, as that article alone lists a few different ways to format numbers.
Leaving open for feedback from others.
This issue has no child issues.
Drupal is a registered trademark of Dries Buytaert.