No, we don't allow the use of unfiltered HTML. It's a potential security vulnerability, and we take security very seriously. There are several examples of the practical implications of this. First, on a Genesis theme, even as the administrator of your site, you won't see the Header and Footer Scripts metabox on the Genesis->Theme Settings menu. Second, embedded HTML in post or page content, such as an < iframe > or < embed >, will be automatically stripped out. Common uses of these techniques can include adding the Google Analytics tracking code or embedding videos. We have other, better methods to accomplish these same objectives, so there's no loss of functionality because we block unfiltered HTML.