I think scorecard you took line from my post....also affects what happens to the account if one of the parties dies.
As I stated have not worked in thai bank but in two other western countries.....
A joint account with both signatures to operate, on the death of one of the parties the account is frozen and goes to probate where usually half is included in the estate of the deceased BUT other party cannot access there portiion until resolved by probate.
A joint account with either signature is not affected by death of one party and the surviving party can continue to draw down on balance of account. Normally if declared the bank will close joint account and open account in name of survivor. Have heard here they require both signatures to close a joint account, surviving or either party could draw down to a minimal balance to circumvent this.