Is the cash requirement of 20,000 THB the same for land and airport crossings in Thailand, regardless of visa status?

Melanie Maddock is inquiring about the cash requirement for entering Thailand via land or air, specifically asking if the 20,000 THB cash requirement remains the same for both types of crossings and if it applies regardless of having a visa. She mentions that her family holds a METV and that they will need to present a total of 40,000 THB for their border run to Mae Sai.