Had Lavabit had in place measures to prevent disclosure of its master key, it would have been unable to comply with the ultimate court order Is this

Had Lavabit had in place measures to prevent disclosure of its master key, it would have been unable to comply with the ultimate court order Is this possible? Can you have a system that allows you access, but doesn't allow you to give access to others? Or is it possible to make a system that not even you have access to and still be maintainable? Edit: Upon thinking about this further, couldn't a solution to the byzantine general's problem like how bitcoin works solve this? e.g. Thinking outside the box here, what if every person who uses the mail system has to collectively solve some hashing problem based on the source code or system change where the solution allows the software patch or upgrade to be applied. If 50% of more of the users solve the hashing problem after inspecting the code, the patch would be applied.