Not true, only if you go to a tax office and have them activate the number for tax purposes. There is a form that you have to fill out to get this done.
I use Bangkok for the monthly method, I just get a statement at six months on the spot, and another at 12 months, no need to wait for Bangkok Bank to order a 12 month statement, works perfect for me.
On number 2, if you want to use your pink card ID number for your TIN you have to activate it at a Thai tax office, there are a couple of forms to fill out.