The entire scam seems to be possible because there is no attempt at confirming the credibility of the people presuming to actually do the peer review. This type of decentralized authentication is precisely what PGP is particularly good at.
I have to imagine that it would be trivial to design a system which would simultaneously ensure that only the actual scientists would be able to peer review a paper based on other (recognized) scientists signing their keyring.
Journals of higher credibility (Nature, Cell, etc..) might even require reviewers that had more authority/signatures on their keys.