Immutable and read-only attributes in the REST world

We have a notion of immutable attributes (section 5.2.2) and read-only attribute (section 5.2.3) for resources. By definition these attributes cannot be changed by the client. One example of such an attribute is 'created' (section 5.3.4). When a client updates the resource (using PUT), does it include these attributes? The semantics of PUT say that PUT overwrites everything at the specified resources. This implies that the client cannot exclude any attributes. PUT cannot be used for partial updates (see http://tech.groups.yahoo.com/group/rest-discuss/message/17421). This brings up some interesting questions:
1) What should the server do if the attribute 'created' (or a similar attribute) is not included in the PUT? Error, ignore the omission, or something else?
2) What should the server do if the attribute 'created' (or a similar attribute) is changed by the client in the PUT? Error, ignore the change, or something else?
3) Is the server required to check changes to read-only attributes?