There already is prohibition for people convicted of a range of offences where there is considered to be a risk to public safety, so it was not clear to us how this was different from what already exists in the law. We know, based on recent Supreme Court decisions, that mandatory anything often presents legal challenges.
As we said in our brief, we don't understand how this is different from what already exists, because people convicted of serious offences are supposed to be prohibited from owning firearms.