Yikes,
Okay, with all do respect dehammer, I'm not going to argue with you. I respect your opinion and I'm new to this community but I've read several other posts and I know there there is no convincing you. So this will be my last response to you.
Concerning point 1
We are talking about water not soda. As a chemist it is vitally important to this discussion that you not change chemicals on me and try to prove a point. Surely you can understand that they are not the same. Also, there is very little disolved gas in water. And the water is no where near saturated with said gas. It is free enough to escape into the head space if it were. So, the gas has no more reason to leave the water when you remove the cap than it did while the cap was on.
On point 2
While you are totally off of the topic I started, I will address this concern anyway. Ice trays? I said nothing about ice trays. Please do not insult my intelligence by assuming I don't know that cold gas is denser than warmer gas. Bear with me, pressure has nothing to do with density directly, only temperature how much you have and the volume of the container.

I'm not going to argue the last point because it's just ridiculous and has absolutely nothing to do with my original post.