That's definitely a reasonable way of looking at it. I expect that if I enjoy the work and am absorbed in it as much as I'd expect probably wouldn't work on new side projects that much, but I do already have existing open source projects and side projects, and I'm worried about that.
Good to know. Is it enforced rigorously within Amazon? Specifically the attention and effort aspect. Do Amazon employees really have to get written permission from Amazon to work on side projects that might make money?
However it follows up by saying unless it relates to the employers research or development. My concern is that since Amazon is such a large company the size of their field of anticipated research and development is so large they can probably claim just about anything I came up with on my own time.