SBK03SE- Ive noticed that the drivers side one (right one looking at it from the front) is more loosely fitting than the passenger side one, mine stays in fine, but if you move around the passenger one while its still in, it has less play then the drivers side, weird but i never thought of it, and around here i dont usually see it.
Just for everyone, i dont know what this guy was doing but i had to snap a pic, this was at BJ;s wholesale market around where i live about 3-4 weeks ago
Seems like you dont mess around with this guy on the road -
(You can see my audi peeking behind it- lol )