It's inaccurate. Have you seen the following CSS codes before??
-moz-border-radius: 20px;
-webkit-border-radius: 20px;
Before the CSS3 standards were finalised, web browser developers created their own special CSS3 interpreters… "-moz" stands for “Mozilla” and “-webkit” stands for “WebKit”. These access the special CSS3 abilities in their native browsers — for example, rounded borders.
In other words, Safari is capable of CSS3, however as the standards weren't released, they were positioned to create “custom browser CSS code” to provide the abilities. Once the CSS3 standards were properly released, will they probably convert to the new standards of CSS3 interpretation.
Microsoft have tested the unreleased CSS3 standards with other browsers, but haven't tested whether or not the browser is actually capable. To prove it, see here. It implies that Safari is unable to do rounded edges in borders, and we all know that isn't true at all.
PS. This is also the same with Mozilla Firefox, which has also been compared unfairly
Now, perhaps Rob can correct me here, but I don't think CSS3 isn't properly approved or released yet.