An acquaintance of mine, a wealthy retiree married to a Thai wealthy in her own right who live in Europe but visit their properties here in Thailand on an average of four times a year, was stopped with his wife at Don Muang and given the third degree. He doesn't bother with visas because they never stay for more than three weeks at any one time and generally weave trips to Singapore and VN into their itineraries.
The problem is that the desk staff are not very bright and cannot distinguish easily the difference between folk who pose no immigration problem and those intent on a de facto residence sans visa.
My acquaintance spent over an hour remonstrating with staff before they finally saw sense. The guy's a fucking millionaire and his wife a former MFA civil servant.
I told him he should get a MEVV so as to avoid future hassles and I think the OP would do well to follow suit. Thai have no common sense and one should always allow for that.