I’ve been reading the responses and it reminded me of the class I took called Business Communications, where they emphasized that CYA style communication was absolute nonsense, your responsibility when communicating is to convey information in a way that can be received, and if that doesn’t happen it’s your fault, not the recipient’s, you can’t control them only you.

So if this is just one person who misses all the questions, sure, it’s them, but you still need to figure out how to get your answers. If it’s everyone, it’s you. Maybe these questions aren’t amenable to email, maybe it’s your format, if you want answers (and not just to prove you asked in some sort of gotcha game) you need to ask the people who aren’t answering why they aren’t.

Everywhere I’ve worked, people answer these by choosing a different font color and writing answers back in the email, but there are not a lot of questions by email. Maybe a note to “provide answers in BLUE” with the word blue in blue font would help?