> In my case, the shutter stopped working with or without the >3rd party MB-D12. > > Until I see some actual proof, in how a 3rd party MB-D12 can >cause a shutter to blow, I'm not sure I'm ready to blame the >3rd party MB-D12.
I think you're right. A shutter failure is usually just that - a mechanical problem that is unrelated to anything electrical in the camera or attached to the camera.
I think it's difficult to imagine exactly how a bad grip - one with an electrical problem - could in any way affect a shutter beyond random firing problems, partial firing problems, trigger circuit intermittency and so on. Mind you, I suspect that just such problems with the shutter buttons and electrical circuits in third-party grips to be the source of a number of camera issues and grip failures.