Not sure where to file this, so please repost to the appropriate spot. And it's not necessarily a bug either, but it should be noted somewhere.
Is Youtube the only provider that uses swfobject? It so, perhaps it's possible to upgrade the youtube provider to use swfobject 2.x?
This issue may affect 5.x versions of emfield/youtube as well.
Anyway, I'll leave you guys to decide how to address this. Thank you.