Earlier quoted context omitted.
I totally get your point – checks and balances are important. However, I don't think anyone is helped by unstated or invisible requirements. It speaks to a high level of mistrust of employees and candidates. Now, if HR were to explicitly add those requirements and be open about it, I'd wager it'd still keep fraud down while also actually improving the hiring process for both HR and the hiring manager.
Fraud is a difficult problem to deal with -- the more open you are about what you're doing to prevent it, the more you speed up the "evolution" of better (aka. worse) fraud. Whether that effect is large enough to justify the lack of transparency in this case, I don't know; but I'm sure there are some cases where it is appropriate. (Marginally related: This is why I have some sympathy for Paypal when they say "this pa…
It certainly isn't going to be common enough that it's worth destroying internal trust and credibility when open (within company) reviews and sufficient internal control mechanisms that didn't include hidden manipulation of candidate hiring could do an equivalent job without reducing the organization's ability to hire stellar candidates (not that I'm biased, given my case, of course =)
I mean, it may well happen, but all sorts of unlikely events may happen and yet would similarly be problematic to keep constant protection for. It's all about the risk/reward analysis and, in this case, I believe you've calculated that incorrectly.