You have to have access a computer to first turn on an iPad, but my grandmother has gone just fine so far using an iPad with no accompanying computer.
If you don't sync photos/music and use the iPad for watching Netflix, email, and web surfing, there's absolutely no reason to connect the iPad to a computer except for every few months when Apple pushes out an OS update.
Owning a computer is a requirement to use both devices.
It's a rather silly requirement on first boot.
I wonder if the requirement is there only because they want to make the user aware of the iTunes sync feature. At this point in the iDevice life cycle, the PC is an accessory to the device, and not the other way around. It's just a nice-to-have.
Is it? Couldn't I just use someone else's to get it all setup/registered? As far as I know there are no restrictions on the number of devices you can sync to a single computer.
I borrowed a friend's computer to provision my iPod Touch. (I don't have Windows or Mac OS X, so I can't run iTunes.)
I can't sync music/movies/photos to the built-in apps (this wouldn't even be an issue for someone with no computer), but I can use the web browser and third-party apps just fine.