@Siggi ******
I am 100 percent sure an immigration officer in Thailand can kjust like in most other countries check if you comply with all the entry requirements.
Where did you get that strange idea that this would not be allowed in Thailand?
Maybe you should Google for it and you will seen that in most countries this just is allowed.
Sometimes you are allowed not to cooperate, but that almost always means your entry will be denied.
And yes, it would be a good idea when admin would stop you from posting wrong information, because when they don't you keep going on posting the silly statement that IO officers are not allowed to check compliance with rules without a court order.