Go in the morning with your passport, a passport photo and 1900 baht cash, complete the form and drop off your passport, the photo and the cash. Come back when they tell you to come back. I suggest you wear pants to be safe.
I don’t think it’s a matter that some airlines ask and some airlines don’t ask. It’s a matter that some airline agents ask and some airline agents don’t ask or some airline agents ask sometimes and don’t ask sometimes. You really can’t predict it.
Nothing pedantic about it. You are giving incorrect information. The only thing I give to Immigration with my passport is the boarding pass from the flight that got me to Thailand. It’s not always, or ever, white and blue and it’s not a TM30.