Can you use the Mae Sai border for visa-exempt entries, and is 20k baht required?

Yes, you can use the Mae Sai border for visa-exempt entries, allowing for up to two border-bounce entries per year, as long as you haven't reached the limit of two visa-exempt land entries. You can also activate another entry on a multi-entry visa at this border. There's no requirement to show 20,000 baht upon entering the Mae Sai border, but you may need to pay a small fee (e.g., $10 or 500 baht) to Myanmar immigration. The border has become more accessible for these entries since the rule changes implemented in late 2016.