@Ken *****

when they do the annual burn-off, it's time to leave.

Good point. Some income might be taxable in your home country. Some might be entirely exempt. Would Thailand tax your tax-exempt superannuation income?

Two issues: how much currency the Thai government permits you to take out and the secondary issue of how much your destination allows you to bring in. Both important to get right.

Onwardticket.com

Perhaps the north American doctors get spooked by the words that follow 'is in good physical and mental health ', ie 'free from any defect' . Perhaps they think in signing that off, they are guaranteeing that the individual is literally free from any defect, not just the five listed diseases, and must test for everything to confirm this fact. Australian doctors would sign off in the spirit of the document: no, the patient doesn't have the five diseases of concern and is, to the best of their knowledge and as they present, in good health. North American doctors are possibly more sensitive to the litigious consequences of making the almost impossible statement 'free of any defect', so protect their interests by undertaking every possible test. I'd be astonished if that was the intention of Thai immigration.