Unless you intend to personally audit their code, I'd argue it couldn't possibly matter. Even businesses like Apple publish all kinds of documentation that belies the reality of their infrastructure. The iMessage Security Overview doesn't mention the NSA's retention period for encrypted communique; the push notification documentation doesn't tell you about the government middleman processing each alert.

You either trust people blindly, or you validate them personally. Getting a pinkie-promise about privacy from the CEO is worth absolutely nothing in real-world security terms.