Actually, I've been hoping someone who has done this will chime in because I haven't done any analytical trials on this situation.
According to the beer thread, it would seem that it does.
Also, when I charged two 2-liter bottles using the connector and then opened and closed it with a regular bottle cap (plastic twist on), it seemed to keep enough carbonation for a day or two. I charged a plastic 2 liter bottle, opened it which released some pressure (but didn't pour anything out) then twisted on it's original cap.
Ideally, the liquid is charged high enough that when opening and releasing the pressure to do the real seal (or filling), then the liquid will release some co2 and then stabilize at the wanted pressure/carbonation.
The problem is, I don't know what pressure this would be, or what temperature would be desired. (From what I gather, the keg would be around 32 degrees F, about freezing, to maintain as much carbonation in the liquid so it won't relese the gas till later.)
After filling the sealed bottle should hold the soda and carbonation without exploding. There is of course the issue about the pressure rating of the bottle and wether soda bottle glass is structurally more stable than a beer bottle, or if they're the same, or not. (plastic already seems to be able to hold a higher rating, or perhaps it's just less of a catistrophic failure than a glass bottle would be if there is a rupture. I don't really know. My packaging degree fails me at this time, not that I ever studied.)