your question tells us you know that you are in danger of being denied entry on arrival. We know that too. Why don’t you just get the proper visa for your intended purpose?
United Healthcare Medicare advantage plan covers me worldwide. In my case, I paid the Thai hospitals when leaving the hospital. A few days later I submitted my online reimbursement claim. About 3 - 4 weeks later, the reimbursement check arrived in the mail at my US home. November to January for the hospital visits and all have been reimbursed to me as of February 11th.
I read the “Terms and Conditions”. I am not shocked that they paid because they established the rules. They won’t ask for a refund because I am following the rules set forth by the insurance company. The difference is that I actually read the fine print.
I live in the US from May to October. I am a US citizen, US resident, US homeowner and US taxpayer. I live in Thailand from November to April in my home in my Thai wife’s village. The insurance company determines the rules, I comply with the rules.