My understanding is the co2 is heavier than air, so the air gets pushed out first- leaving a 'blanket' of co2.
Your suggesting pulling the tube out is so significant that the displacement draws air in to the bottle.
I can see that.
If this is true, and lets say it is. Wouldn't the beer gun be the easier solution as you can quickly tap the trigger and give one last blast of co2 to the top of the beer?
Pop! Move on...
I'm ordering mine this week. I don't have any personal experience with it yet, but every youtube video makes it so obvious that it's the easier tool to use, the price difference shouldn't matter. I keep scratching my head at the comments that sort of say, "I don't bottle a lot so the difference won't matter." I keep thinking, if one beer is irritating, then it's an irritating tool. The Beergun seems to be easy every time. Frankly, this post has got me asking myself, why am I waiting?
Oh yeah, pay day! Then I'm buying a beergun- and I'll use it to cap my beer with co2 (at the end).