Why would you forbid other clients than iPad to browse into your site? I think you should warn the user that it may not be optimized but let the user in.
It's irritating, the web should be open.
The tech is made specifically for touch enabled devices right now. Other tablets don't have market share, so we're focusing on the sector of the market that's 97% of readers. Once we nail that, we'll spend time on another tablet browser when it gains market share.
Yeah, that seems perfectly reasonable for me. But once again, you could just state that it may break and is not made for your browser, but there is no reason to not show the content, and more drastically, even forbid entrance.