Are non-B work permit holders prohibited from land crossings in Thailand?

There are rumors on Koh Tao suggesting that non-B work permit holders can no longer use land borders to exit Thailand and must instead leave via airports. The poster is seeking confirmation about the validity of this rumor and whether it applies to all borders, especially given the lack of direct flights from Surat Thani to Malaysia. Responses include suggestions for alternative travel routes and commentary on recent experiences crossing borders.