[kelnos]

> two different owners simultaneously believe they are the sole owner of an object.

Not in the sense of ownership that matters in Rust. The Vec owns the data. A node with an index in it does not own that data. It merely refers to it.

The key here is when you answer the question, "what happens when I screw it up the indices?" And the answer is logic errors or a panic. Neither of those are memory safety issues.