Hi David,
That would work as a GotS option only if the iframe is viewing a page on the same domain. Once the user navigated to another site (say, JSTOR) in the iframe, browser security restrictions prevent us from touching anything related to the framed page, including the JavaScript.
If GotS is on the same domain as the resource, that could work. I'm not sure, however, that that's a general enough requirement to include it in GotS core (how many tutorials stay on the domain the GotS app is on?), though if people disagree I'm happy to hear arguments for including it.
Mike