mememax - 8:50 am on Dec 9, 2011 (gmt 0)
Hi Adam. Google will always show the most restrictive keyword. If you set two identical keywords for two different regions like california and florida, that SHOULD not be an issue because google SHOULD recognize the user location and user intent (if you configured the campaign like this) and will show the keyword matching those geo-filters.
In my own experience, google editor will show me those keywords as duplicated. The only way you're sure to not activate double serving issues is to point to 2 different domains. Build a site for each region with its own campaign (or account if you prefer).