I think Flock is probably the worst solution besides all the rest. They seem to be the most auditable and accountable. The fact that anyone even knows the service and founder is a testament to accountability.
Try to get something out of the CEO of Bank of America or some other faceless corporation
(Yes, I know that shareholders have the ability to vote on board proposals as well, but even if you think those mechanisms are equivalent, there's a pretty huge difference between "if you buy stock, you get the right to vote" and "you have inherent human rights including but not limited to the ones enumerated by a written constitution")
I have. It's easier than you think.
As opposed to their mayor/governor/president, who they not only can easily find out who it is if they don't already, but can also vote out (and who often will have term limits)?