FYI: My friend went to Chaengwattana immigration last Friday for 2nd extension as her tourist visa expires on 19th this month. She did not want to wait until the visa amnesty ends as there will be a lot of people then. She was advised that her visa is automatically extended until 30th without stamping on it. She also did not have to pay for anything. When she asked if she can come back then, she was told that she needs to go out of the country.
You can automatically turn off comments for this posts as I have no additional information. I am just sharing what happened so everyone can prepare what needs to be done.
TLDR : Answer Summary
A friend visiting Chaengwattana immigration reported that her tourist visa was automatically extended until the 30th without a stamp or fee. However, she was advised to leave the country before returning.