I took advantage of an early start to go for an easy, wandering ride. I explored some trails in Irvine Regional Park, and checked out Peters Canyon a little bit. (It was fun, but really crowded. I won't be back to Peters on anything but a weekday lunchtime ride.)
Unfortunately, a post-ride cleaning & inspection turned up a nasty crack where the top tube and seat tube meet. It's well-advanced, and runs nearly half-way through the seat tube. So this frame is, to borrow a phrase, dunzo. No more trail rides for me for a little while.
Happily, I have all the documents from the original purchase. (The office filing cabinet is my secret weapon.) This should, I think, be covered under the bike's warranty. We shall see.