Sources: RIM [Patch Press Release], RIM [KB Security Advisory], Twitter-Chris Wade
quote: You misunderstand the problem. If they find a vulnerability then it can be used for malicious software. If it was just about permitting other OS's it wouldn't be a problem.
quote: In our system we have the ability to deny mobile devices that have been jailbroken. Once your on the environment if the user jail breaks the device its then blocked from all communication. Not sure how the system is able to determine it but its in there for both iPhone and Android devices.