Private citizens maybe but I think e-mail and cloud storage providers should be treated more as "common carriers" and only respond to legit legal requests for such data rather than enthusiastically embarking on witch hunts to do law enforcement dirty work. What you're sort of advocating would be like the post office reading all of your sealed mail in just in case you might be a pedophile and letting law enforcement know you might be a pothead.
Why shouldn't I expect the same rights that I enjoy (theoretically, not in practice) with telephones and snail mail to carry over into the digital realm? The USPS is govt run in name only these days and is more of a private organization. Would you be cool with UPS searching all of your packages because a computer said there could be pictures of underage titties in there somewhere?
What this boils down to is the government is using private companies to circumvent the constitution using the same old "think of the children" tripe that brought us the drug war with a double-dose of tyranny and it's sickening.