Check local laws

In more than a few countries, asking a government ID over the internet is illegal. (For pretty obvious reasons, DUH!) Of course, CHECK LOCAL LAWS. But you have a good shot at answering this depending on where you live, or claim to live - and then either dropping that requirement, or if they continue to require it, sue them back or at least threaten to.

I would also add that while it is illegal to forge a physical government ID, it may not be illegal to draw one on your computer, print it and scan it back. Most of the security features which depend on lighting cannot be scanned. Numbers or barcodes only make sense to local law enforcement (and maybe locals with knowledge of what they mean) - but again, CHECK LOCAL LAWS. Even this may be illegal where you live, or at least with some documents.