you're kidding yourself - IMHO.
You've never had to rescue someone for real, have you?
We have. One of our divers died during a dive because he had a serious heart ailment and lied about on the medical form because he *really* wanted do this...
Another was prone to panic attacks but lied about it. Without any warning at 25 metres (83 ft) he ripped his mask off, threw out his regulator and breathed water... This one we saved despite his best efforts to the contrary.
Another, one of our own staff members, nearly bit it from a heart ailment on a wreck dive in the middle of the North Sea. He knew he wasn't well but didn't want to hear what the doctor had to say.....
and THAT (the last one) is what the medical form is for. It's forcing people to seriously consider the risks and not to minimize them, hide them, or ignore them.
Like some of the others, I find your advice about lying lousy, to say the least.
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That said, I find the OP's question very interesting. I've never thought about it before but doctors have a professional obligation to secrecy about their patients files. I would say they are held to a much higher standard than dive pros are in this respect.
Unfortunately I don't have an answer. We need this form or we can't train you. It's that simple.
It would be nice if there were another form for the MD to sign off on with the same list but with the requirement that the MD signs off that he/she has considered these risks. That way the MD could sign you off "fit for diving" without the dive pros being privy to the details of the doctor/patient relationship.
Unfortunately such a form does not exist.
R..