Composed resources are still claimable

[muvaf]

What problem are you facing?

Claims bind to resources whose binding status is Unbound and composed resources never become Bound

How could Crossplane help solve your problem?

Composed resources shouldn't be claimed by others.

[negz]

Any managed resources that are composed into a composite will have their controller reference set to point to the composite. I don't think there's ever a situation where a managed resource with a controller reference is a valid target for a claim that sets an explicit resourceRef, so perhaps we could solve this by adding a check to the claim binding Bind() methods that refuses to bind to a managed resource with a non-nil controller reference.