@JustAnotherNomad the international insurance by Cigna for $4000 if you are in mid thirties will cover you worldwide excluding USA. The annual limit is $2,000,000. Cigna has also international plus plan with unlimited coverage, don't know how much it costs... Aetna for example cost the same but offers coverage annual limit of $4,000,000. The devil is in details. You have to spare few days to go through policy wording of each and find which do you feel most comfortable with. For example Aetna despite double the coverage limit, doesn't cover any brain related issues. Others don't cover development disorders e.g. Globality (important for newborns). There will be always some exceptions, bigger or smaller. Bupa Elite, which includes US, comprehensive dental and has one of the least amount of exclusions, has annual limit of $5,100,000 but it costs $11,000 per year or $10,000 if you opt for 20% co-insurance.
Your example by the "German guy living in Dubai, who went to Germany for surgery" would most probably get covered by all of the above.
I understand your concerns, as I share similar, but going through policy wording of 20+ insurance companies, I can guarantee you there is no "one to rule all". If someone plays dirty, there is always a way to kick you out from the health insurance plan. What if Globality won't kick you out but will increase the premium x10 ? This is what happens with some health insurance providers, they have TIERS they put you in for renewal depending the amount you claim or how risky your health become to them during your "relationship".
Globality wording:
"If the treatment or other measure for which benefits have been agreed is more than is medically necessary or if the amount claimed for is not within the usual, customary and reasonable, we will be entitled to reduce its payment/reim- bursement and the insured shall be responsible for all costs, which are not within the usual, customary and reasonable, as we do not cover any amount, which is not within the usual, customary and reasonable."
So even if you have $10,000,000 or "unlimited" coverage it doesn't mean you can go to the best clinic in the world, be operated by the top surgeon and you won't have to pay a dime. It doesn't work like that.
I agree Globality is very interesting option and I was myself very interested in it, before they were called DKV Globality, their offer was always impressive. I know those who got insured before DHA regulations kicked in, could continue to be covered even with Dubai residence visas but for new clients they are a bit wary.