One of the things that I find funny is the number of people who don't want to disclose a health issue "to someone who has no medical training" who are perfectly comfortable with their OWN lack of medical training to determine that their medical issue has "no potential to cause a problem."
Trust me, putting my life at risk by having me jump off a boat in the middle of the ocean to save some idiot's @ss will make my life - and their's - much more difficult than if they had been honest on the form in the first place.
If you think rolling a body over in the water, immediately realizing the person is gone when you see that they are blue with pink foam coming from their mouth and nose, towing their lifeless body back to the boat, having five people struggle to pull the body up onto the deck, waiting for what seems like hours for the Coast Guard chopper, loading them into a basket lowered to the deck of a boat that is moving through 4' seas at 10kts, crossing your fingers as they're hoisted up, and never seeing them again, is NOT DIFFICULT...but getting a medical form signed by a doctor IS...I suggest you think the whole thing through again.