To answer your point, combatting tax evasion is not oppressive nor a witch hunt unless you are a tax criminal or involved in money laundering, child porn, drug running, gun running, car theft or other criminal activity!
Thailand is part of FATCA and the common reporting standard! Not sure that they routinely report such facts! However everything that you do through a bank would be traceably and reported! If u have a bank account here and you deposit money that would and is reported! If someone else deposits money into your account here that will be reported!
TM30 has been around for decades! He will know unless he lives under a stone, problem is u are both breaking the law! you need the tm30 for everything now! I suggest u go to immigration or move!