I think it’s safe to say for the general case that if you have millions of widely-shared smart pointers you are not following RAII principles. At that point you are left with poorly-implemented reference counting, with a ton of synchronization overhead.
If the lifetime of your objects are not bound to any scope, I’d say you’re well out of the realm of any real benefit that RAII would provide over GC. This is a continual problem that arises with a shared ownership model. The specific principle this violates is encapsulation - there is still encapsulation at the level of the smart pointer, but not with its consumers.
