Read the Thai goverment website about the workcation DTV clearly says you can work in Thailand but not for Thai Employer. The guys who applied for this type of visa had to submit portfolios online links to you tube channels etc.
Well one of reasons DTV came out was after the popularity of the videos by Cullen a korean guy and his mate who visit all national parks and other offbeat locations around Thailand and they were even mentioned by authorities as likely canditates for this type of visa. They make the videos in Thailand.
its up to the airline, last year i would say about 50 % of the time i got asked for proof of onward travel or visa and delta didnt want yo do it with showing visa. Guess i took about 20 ish flights last year