That's an interesting argument but the hash for an "infringing file" would be universal across all copies of said file, since presumably the DMCA striker would be claiming the file as infringing. I doubt a jury would buy it.
They can claim that a file is infringing everywhere it exists but they'd often be wrong and I don't think inherently infringing files are a valid way to interpret copyright.
"Better safe than sorry" is certainly, uh, safer. But I don't know if you can really say the DMCA requires it.
