Election officials could assign "strict" signature validators to certain targeted districts, so approx 10% of ballots get thrown out, and "loose" validators elsewhere, so only 2% of votes get tossed.
That would be illegal. See the “Bush v Gore” decision which was about a similar idea but applied to counting hanging chads, etc. rather than signatures.
Of course it is illegal. The discussion is about how anti-fraud measures (like signature verification) could potentially be flipped to actually assist in cheating/fraud.
Let's keep in mind, depending on where power lies post-election, that doing something illegal, even if caught, doesn't necessarily means one would be punished for it.