Some users who uploaded videos DONT have the problem. So it's not ubiquitous. But MOST users who uploaded videos DO have the problem.
I do find it odd that the one video that showed himself not having the problem was removed from youtube, however.
Here's a video of someone demonstrating a way to test the issue because *he* suspects it's an "every iphone4 issue". People at his company tried the key on 6 iPhone4s, and every one of them had the issue.