Not sure if serious, but no. Anyone can copy a favicon; the point of an identicon is that it's generated from the domain name, so subverting it would require an attacker to find a hash collision with a visually similar domain.
However, teach users to read domain names! If users do not grasp the general concept, e.g., if the supposed identity is just "example" (possibly with some decoration considered insignificant) and not "example.com", how are they supposed to survive? Domains have been around for more than a quarter of a century, the Internet is actually part of our lives… There is no excuse, and there is no sense in pretending that there was no harm in not understanding the basics. That said, there are real ambiguities that have to be addressed.
FFS, if users cant see that somedomainname.com is different than somedomanname.com how does a randomized image of the domain name based on a hash solve this.