We've heard so many sad stories in the past about ones who accidentally lost their jailbreak, or thought they could go back to a previous firmware when they couldn't.
As jailbreak aficionados that truly saddens us. Hence, whenever we can help get out a warning, we're all about it.
The iPhone Dev Team, the folks responsible for tools like RedSn0w, PwnageTool and more, have sounded a loud warning about the iOS 5.1 firmware, and its implications on jailbreaking.
If you're at all concerned with jailbreaking, we highly recommend you listen up...