“from what [you] you have been told…”? I have lived and worked here since 1998, and since that time I’ve seen many foreigners who were scammed or extorted by visa agents and unscrupulous local lawyers. Just finished a trial against one.Naïve to think there’s no risk in using these people. It’s highly risky.
Stay compliant in Thailand. Foreigners often get into serious trouble then they try to use "short cuts" with dodgy agents and local lawyers. Can't complain to anyone when that happens. Play it straight.
Preventing foreigners from becoming a burden on the Thai state because of health problems makes sense, but if that is really the rationale isn’t proof of insurance a better way to address that risk?