It's likely that Paul Graham directly and enthusiastically introduced them to the VCs, which obliged them to respond with a semi-coherent rejection. That's what the Fred Wilson rejection was like anyway: http://www.paulgraham.com/airbnb.html
You're right. That makes a lot more sense, especially the $1.5M valuation. I missed the first line about Michael Siebel introducing them. Given his YC affiliation, it probably had a similar effect.
I think that's also wrong. Michael wasn't a YC partner at the time; he joined Justin.tv as CEO after Justin and Emmett got into YC again after selling their calendar app to Tucows or similar on eBay.
