I must admit I didn't put much thought into my comment on ethics but I guess what I had in mind is perhaps a scenario where the behaviour is not actually intentional, and the vendor should at least be properly informed that there may be leakage (to them) of private data as opposed to just jumping straight to blogging about it.
So rather than "responsible disclosure" perhaps just a code of conduct to ensure that such a program doesn't just attract people looking for glory and blog posts, but actually has a standardised way to report these issues to the vendor and give them an opportunity to fix and/or respond.
I don't mean to dilute the core of the idea though, it's a good one, and it definitely needs to be geared towards being in favour of the consumer rather than letting the vendor off the hook.