You are misinformed about GSB pink bank. Actually my wifes friend works in the local branch and we think she has high integrity. She told us that many VERY wealthy people in Thailand trust GSB and put massive deposits with them. This is not some story Im making up.
Agriculture bank is also a govt bank. I have money with them as well.
Cant go wrong with the government banks. I dont know about the 2nd tier retail banks.