I would do that but make it pseudonymous. i.e. illegal or fraudulent content is clearly owned by the user irongoat, and you know who irongoat is (at least you

I would do that but make it pseudonymous. i.e. illegal or fraudulent content is clearly owned by the user irongoat, and you know who irongoat is (at least you know their email, IP address) but no-one on your site knows who irongoat is. If the content is bad enough, authorities will get in touch for you to tell them what email address irongoat is associated with. But as long as the content is OK, irongoat can say what he/she wants, with no PII visible.