Leaks are a "bad" thing in the same way that Snowden's Top Secret files leak is a bad thing: a developer signed a non-disclosure agreement and violated it. Whether the intent was altruistic or not, the fact is that a legal agreement for confidentiality was broken, and potentially, information related to features or other things of competitive advantage to BlackBerry could have been lost or exposed. If this were Apple, that developer would have been found and there would have been some pretty severe consequences for that person..
That said... Leaks are also a "good" thing in that they allow BlackBerry to do a couple of things: get some additional unofficial testing and feedback, and to, again, unofficially, circumvent "carrier testing" requirements and get bug fixes out into the hands of users.. BlackBerry has always had, in my perception, a problem with incomplete or insufficient testing: they'd release a new OS, and features that were working in the previous release are now broken.. And we're not talking obscure functions that nobody uses, but often core product features.. Obviously, their internal testing and regression procedures were not sufficient to catch these problems, and their set of "beta test" developers were obviously focused on the new APIs or functions that they were interested in for their application and did not bother to re-test core functionality.. By turning a "blind eye" more or less to leaks, it allows them (assuming that they pay at least some attention to the various public forums where leaks are discussed), to get some additional, unofficial testing and feedback and to address such problems, if not in the next "official release" (which are probably older than the leaks and already in the hands of carriers), then in an upcoming release.. They have gotten better in the last couple of years, but there are still too many bugs IMO.. Secondly, and I have it direct from the lips of a VP within BlackBerry, and I won't mention his or her name or which part of the organization they work for, but a very senior executive level person, so they were espousing an "unofficial, semi-official" corporate position with regards to leaks: that they tolerate the leaks (they eventually get files removed from hosting services, but they take their time), at least partly to get around the long "carrier testing" periods and get some critical bug fixes out to at least part of the user population. They have been working on processes to try to reduce the carrier testing required and are looking at ways to decouple security and bug fixes from things that may affect the carrier network, and I do see some improvement, but the carrier approval process is not global (so some customers are stuck with ancient OSes with all manner of bugs) and is creating a huge amount of frustration within the user community, so I applaud BB for not clamping down on a channel that in all fairness they have a right (and indeed, perhaps a corporate duty) to clamp down on..
So, I say, let the leaks continue!