Has the Mae Sai border bounce changed from a $10 fee to a 500 baht charge?

The Mae Sai border bounce fee has generated questions about whether it has officially changed from a $10 charge. Recent comments indicate that the standard $10 US bill must be in mint condition, or it may be rejected. One suggestion is to carry both a 500 baht fee in coins and a crisp $10 note to see which payment method is preferred at the border.