I'm not asking about your particular moral judgement.
What I am asking you is the following question:
I have a medical condition listed on the form which I know with absolute certainty is not relevant in my particular case because of the specifics of my case. I have had recent dive physical (well within the 1 year that PADI at least requires) by a qualified physician.
I answer "No" on all questions and sign off on the form for the reasons that: I am not willing to disclose my medical information to someone with whom I have no medical relationship; I have the specific medical clearance that they require; they provide no guarantee that they will accept my clearance even though they have no ability to evaluate medical information; they have no duty to protect the confidentiality of my information; there is no liability on their part for failure to protect my information listed in the contract; they are not willing to negotiate the terms of the contract; and lastly that it does not change any liability issues or waivers relative to the contract.
In what way have I created a problem?
Look at the PADI form again, I believe it addresses at least some of your concerns:
http://www.padi.com/english/common/courses/forms/pdf/10063-ver2-0.pdf -
At the top of Page 1, it says "(Confidential Information)". This means that PADI and their associated dive operations have assumed the legal obligation to protect the confidentiality of the information.
On Page 1 it clearly states (in two places) that if you answer "Yes" to any of the questions you should get a doctor's approval prior to diving.
On Page 2 is a form for a doctor's approval. It requires the doctor to check one of two boxes, which say either (a) "I find no medical conditions that I consider incompatible with diving", or (b) "I am unable to recommend this individual for diving." This statement does not ask for specific medical information.
On Page 6 is a lengthy list of medical references and endorsers, which include major hospitals, barotrauma centers, and DAN resources. I presume that these experts have approved this form from a medical perspective. I suppose you could challenge it on legal grounds, but I doubt you would prevail.
In my opinion, since you already have a doctor's approval, you should check "Yes" and present the approval.
If you mark "No" when the truth is "Yes", have you created a problem? Possibly. There are endless scenarios. For example, if the dive op's negligence results in your being injured or killed, you or your heirs will have to disprove the defense's charge that it was your own failure to discose requested information that in fact caused the incident.