I really don't see how any of this is incompatible with the checks of warranted search.
Compulsory digital surveillance sucks, don't do it, but if it's required else the data is lost forever then it's required. (if you agree with the legal access to private data)
This is not complicated, you don't need to make it so.
What I think you are saying: it would be okay to force private citizens to keep tabs on each other so long as the warrant/subpoena and court system were trustworthy and in working order (i.e. in the case where there are very few abuses and mistakes by law enforcement).
(Also note that it isn't law _enforcement_ that we are talking about.)
Nor is it an intellectually void hypothetical. The Stasi did exactly this not so long ago.
Finally it appears this isn't what you meant in your post. What did you mean in your post?