The purpose of Capture, like so many things in GTD, is stress relief not stress creation. For Capture to relief stress, you have to be comfortable with the action of capture and if your in an environment where you not comfortable, just let it go. If its a thought worth having, it'll show up again, and if it wasn't and it doesn't then it doesn't matter either. Try not to let Capture be a means of capturing stress.

Another primary purpose of Capture is to get something out of your mind so that something else can show up. Have you every worked on a presentation or a writing project in you head and had some brilliant thought that you want to hold on to yet you can't yet write it down? What happens as you try to remember? Don't you stop having additional thoughts because you're too anxious about forgot the thought that you think is really good? Thats the major reason for Capture so that you can keep going, in other words it's the opposite of capture, it's letting go and getting your mind free to have and to hold more things. It's a process of emptying not collecting.

One of the downsides is that once you Capture something you might feel that you have to do something about it, that there needs to be some elaborate process to realized the fullness of this thought that got you to write it down in the first place. The problem with writing all this stuff down, even though it is vital, is that is still can gum up the works. So you need practice letting go many of the things you Capture. I think that if GTD turns you into a Capture Pack Rat, you're likely to be consistently frustrated by this wonderful collection of habits. I see this happen all the time.