exeption when used <style> tag

We use CKEditor 3.0 (revision 4148) in our page.

Sometimes users got exceptions:
Please remove "<style>" in your post. We needed to block this html tag since it was abused by some users
Inline styles are OK to use such as <p style="background:#ccc; color:#fff; border: solid black 1px;">.

Is this exception internal in CKEditor 3.0?

Thanks.