It didn't take long for the second beta version of iOS 6 to be jailbroken. Already version 0.9.13 (Developer Build 2) of Redsn0w allows the jailbreak of the new iOS.
However, it is very possible that Apple is waiting for the last moment to close the breaches that are used to jailbreak the beta versions. It is the best way for Apple to prevent hackers from starting to look right away for new breaches. In any case, it is almost certain that Apple will get rid of these breaches that were used to jailbreak this beta version before the final version is released.
As a reminder, a breach allowing jailbreak is still a security breach as it allows third parties to execute code without any security check from Apple. If it is not closed, it could be used, once it is known by other hackers who could use it to run dangerous code for example to install apps that would run in the background and call expensive phone numbers.