Why You Need A "Return" Ticket For Thailand

Way back on this thread, someone pointed out United Airlines procedures for flying Stateside to Thailand. And, yes, when checking-in on-line, you no longer can print out your boarding pass, and avoid any and all United ground folks until you enter the jetway (a few years back you could -- as I never check bags, this was pretty cool, even tho' I had a visa, so wouldn't have experienced much hassle). Instead, you have to check-in with a ground agent, in order for them to see: 1. Your visa: 2. Your out-of-country ticket: 3. Your Thai passport, if a dual citizen; or 4. Your cogent explanation of, what all those stamps mean next to your Non Imm O visa that expired 8 years ago.

Anybody have experience with checking-in on-line with Delta (the other US carrier to Thailand)?