-//! To make this work, it is crucial that we can actually rely on `drop` being called.
-//! And, in fact, this is a guarantee that `Pin` provides.
+//! Crucially, we have to be able to rely on `drop` being called. If an element
+//! could be deallocated or otherwise invalidated without calling `drop`, the pointers into it
+//! from its neighbouring elements would become invalid, which would break the data structure.
+//!
+//! This is why pinning also comes with a `drop`-related guarantee.