What happens when multiple container roots share the same identifier?

My read of the spec (see below) an testing in chromium, suggests that identifiers are not actually required (i.e. <div containertiming> works), nor do they need to be unique.

However, every unique container (node) creates its own unique Container Timing Record.

It seems equally viable to me to consider sharing Records based on the string identifier, rather than the unique node. (Thought I do like that all unnamed nodes always just create a new root).

• a containertiming attribute will mark a node as a root, and add the node to a global map or roots.

  container root records map that maps container root Elements to Container Timing Record objects.

• Whenever any element paint happens, we merely walk up to the nearest root (https://wicg.github.io/container-timing/#handle-element-painted), add attribute the paint to that root.

Read the linked Container Timing specification sections for the containertiming attribute, the container root records map, and handle-element-painted. Determine whether records are keyed by the unique Element or by its string identifier, including the behavior of unnamed roots. Done means the specification's treatment of duplicate identifiers and unnamed nodes is explicitly decided.