A factor that is easy for developers to overlook is that the legal system still cares who owns the hardware. So if all your stuff is at Amazon, a warrant can be

A factor that is easy for developers to overlook is that the legal system still cares who owns the hardware. So if all your stuff is at Amazon, a warrant can be served to Amazon and they will let the cops into your stuff. No contract can keep that from happening. If a company (or person) really wants complete visibility and control into their relationship with law enforcement, they have to host their own hardware... ideally, their own data center.