You don't get to pick and choose on a spectrum of "obeying the law." The DMCA is so poorly written that even a little hesitation or restraint causes a business to lose its liability protection under the "red flag" tests.
To preserve its safe harbor protection an ISP must take material down whenever it receives a DMCA notice. They DMCA notice also relieves the ISP from potential liability to the owner of the site taken down.
But what should the ISP do if it receives a piece of paper with the words "DMCA Notice" at the top but it does not contain all of the legally required information? Take the site down anyway? Then they could be liable to the site owner. What if some of the answers are not just hard to believe, but actually nonsensical? What if it is signed "Mickey Mouse"? Or what about this requirement:
''(ii) Identification of the copyrighted work claimed to have been infringed, or, if multiple copyrighted works at a single online site are covered by a single notification, a representative list of such works at that site."
What if the complainant wrote "The copyright protected work is my name, John Jones." That is a nonsense answer. It is not much different than writing "Not telling!" or "Get lost!" in the space. I would say that the ISP should send the request back with a note that it is not a legally valid DMCA notice. The ISP is not expected to verify that the information provided is true, but they should verify that all of the required information is present.