My friend and her roommate, both with white CD MacBooks, had the same wire-coming-loose problem with their power adapteres. The problem on their adapters popped up within a couple of days of each other. Both got replacements on the spot at the Apple store, with similar "we don't usually do this type of thing" stories from the geniuses.
That story must be standard operating procedure at all Apple stores.
My MBP's connector looks like the old version. I hope it doesn't come apart. I have it sitting on desks and tables (as opposed to my lap) about 99% of the time and it's not getting stressed.