Are South Africans being refused border runs at Myanmar, and can I cross into Laos if denied?

South African are a bit on Thai Immigration watch list and your own government add to some problems. In principle SA if the only country from the African Continent that enjoys the same privileges than a Western passport. Mean you can enter by Air for 30days visa waiver, you can do border bounce in one calender year TWICE and you can apply for Visa in some countries. Now comes the tricky part, some places don't accept South African passport. I do not know why. For border bounce you have to check with the companies in that area, they would know best. I can tell from Bangkok you can go Cambodian border without problem (just avoid POI PET). Kanchanaburi border will not stamp SA, however I can not speak for Mae Sai. All border with Laos are OK. Coming to next part: Visa application: Thai Embassy and Consulate in Laos can issue Visa to SA and in Malaysia at Kota Bharu. Other places in Vietnam, Malaysia (Penang/KL) and Yangon do not issue Visa for SA. Last point the SA Embassy, take ages to get new passport or get documents certified. Very last point: if SA apply for an informal ED Visa you will have to show Police Clearance report and must have a valid story of why you wish to study Thai. Best would be to sign up at a real University to get real Study paper.

I wouldn't read too much into it regarding nationality seeing how many thousands of visitors from each country visit thailand. Just because a couple of South Africans had trouble doesnt mean they are being targeted. People have a habit of not sharing the full history when being denied.