That is, anonymous posting becomes an "insurance policy" against negative experience.

It can also become an insurance policy against positive experience -- reclamied posts gain no XP :)

Second, this can lead to a malicious use, where someone posts anonymously and a second person claims it for him, say, when he walks away from his desk.

This is not so much important I think (if your desk is insecure, well, not perlmonks problem)