That may be it, though it's odd they would block it even before final versions of Flash have shipped for any mobile device. For the PS3 and other platforms, they only blocked it after people were using it.

It's going to be a big disappointment though if people run out to buy a mobile device that supports Flash, to find it doesn't support Hulu. I really wish they would figure out what they want to do, as I'm really liking the idea of just watching what I want on on a non laptop portable device. As it is right now, I still find it easier to go to Frys and buy a DVD box set of a show then figure out where online to get content.