If you actually think those forms serve any purpose whatsoever, except to give the operator SOMETHING to possibly fall back on (i.e. "not our fault he died, he has a history of convulsions" - "not our fault she died - she indicated she might be pregnant - that's what killed her" or whatever), you're kidding yourself - IMHO.
Regarding the rest of your post, I agree. Even during the first night of class, I can't remember if anyone answered "yes", let alone what the condition was. From how I use it as an instructor, it is part of the checklist of items that must be complete before I can teach you. If you want to lie on the form then so be it. The only time I have used the form for other purposes, we had to call 911 for a student once, and we referred to the form to see if we should give the paramedics a heads-up on anything. This student answered no to everything, so we had nothing to tell.
I think the other purpose of the form is to provide some sort of information to the student. Something along the lines of "hey, you might want talk to someone about this before you dive" type of information. To blantantly ignore the forms and answer no to everything might be risking more than the class is worth.