Do reviewers really not know the identity of authors in fields that frequently use arXiv? The point of peer review is anonymity but since most authors upload their papers to arxiv long before the paper is published (at least for math, stats, computer science etc), the reviewers should see who wrote the script by simple googling right? Will this have an impact on the review process? That is, a famous scholar's article will more likely be accepted to top journal given similar quality.
It is in fact often easy for a reviewer to find out who an author is, unless the author is quite  new to publishing and has not uploaded the  paper to arXiv.
Sometimes it is hard not to know even without a search since the author may be building on their previous work so the list of references will be a giveaway even if the the text doesn't refer to &quot;my previous work in [reference]&quot;.
That said, refraining from such a search is implicit in the unwritten contract between the reviewer and the editor.
I hope and suspect most reviewers honor that contract.