For anyone considering a bounce at Sadao, my friend just came back. Despite the horror stories, he said it was remarkably easy and he got a 30 day stamp.
-He did NOT have to enter Malaysia (or stay overnight).
-He did NOT have to show 20,000 baht.
-He did NOT have to show an onward ticket.
-He DID put 300 baht in his passport before entering Thailand. Seems like that helped.