Hotel or owner of the property you stay should do TM30 within 24 hours from your arrival, you or any person who you give your passport and other documents should do TM47 at the immigration office the district where your most recent TM30 was.
Anonieme deelnemer 342 You don't have to agree, I cannon help you don't understand such simple economic principes. The fact you are unable to understand does not make it BS.
The fact you call it ridiculous shows you just don't understand how things work. You do not pay for costs, you pay for a product or service. No matter where you look, it works that way. Bigger cars have higher marges than small cars. For the bussiness class in an airplane you pay much more than only for the extra space. Look around and you will see this pattern everywhere. You don't pay for a minivan ride, you pay for a borderrun.
Maybe not worry about it, it is too late now anyway.
Leaving the country will not change the fine with next interaction with an immigration office, where they might, or might not charge the 2000 baht fine.
When you both comply with requirements it might be better to apply independant.
In case the both of you don't always leave and enter the country at the same time, the dependant cannot get an in country extension when the other not gets an in country extension.
Not a big issue, but in some cases it can cause problems