During the announcements Q&A session Niall Kennedy determined that the current RSS output that the new structured blogging standard was outputting was not in line with W3C validation standards for RSS. The flaw was addressed by the structured blogging team by Marc Canter in saying emphatically:
"We will fix it."
According to this recent post on Marc Canter's blog in a post titled Keeping Niall Happy, it appears they have kept to their work and fixed the validation issue in question. Nice work by the Structured Blogging team in getting this fixed and keeping Niall happy.