“....
The "hassle"... She said "they were curious why I always came to Thailand every 3 mo for over 2 years". That's all. And it seems to have been resolved amicably...”
Not to cast any aspersions or to infer anything negative about the OP’s gf, if she was traveling alone, there maybe another reason immigrations gave her difficulties. Once again, I mean no disrespect and not to offend, just offering a theory for that situation, as Immigrations have been known to crack down.
Refer to Thai Immigration Act B.E. 2522, Chapter 2, Section 12, Line 8.
http://www.samutprakanimmigration.go...ration_Act.pdf