I have a travel health insurance that covers my current trip, always had one as long as I stay away no more than 6 months I'm fully cover to up to 1 million.
I have always been here as a tourist since I started travelling in Thailand in 2000 and I have always respected their rules.
Sometimes I have been here on exempt visas, sometimes on single visas, sometimes on multi entries visas, sometimes I have asked for extensions but I ALWAYS respected the current rules they had, have.