Contributions from anons can and in most cases will be verified by maintainers. The actual problem here is appointing them as maintainers.
EDIT: To be clear, this problem is not directed to the original xz maintainer, but more about how to prevent or reduce such appointments in the first place.
EDIT: To be clear, this problem is not directed to the original xz maintainer, but more about how to prevent or reduce such appointments in the first place.