I thought the chat would default to group chat. When I attempt to send a message, I get the no recipients specified error, then I cannot do anything else. The game does not appear to be locked up, but my keyboard appears to be stuck over any buttons I could use to rectify the situation. I can't find a way out and gotta force quit.

I figured out everyone is deselected by default.

I recreated the OP's situation, and I can confirm this bug.

If you happen to get stuck in this situation again, just delete everything that you typed on the chat box, then touch anywhere on the upper screen. Then, you can interact with the "No Recipients Specified" box.

Thanks for the bug report. Which device are you using?

Never mind. I was able to reproduce it on an iPhone 4. Added to the list.