What do the 60 days x 2 rule mean for UK passport holders in Thailand regarding calendar years?

@Wayne ********

I've flown into and out of Thailand on 13 different airlines and never got asked about return tickets. Having said that all my tickets were e tickets supplied by companies. The only time I had an issues was at Suvarnabhum checkin for Finnair one early evening. I gave my e ticket to the check-in girl and because it was bought by my company as a seamans ticket, which are cheaper, the girl asked if I had a seamans book, which I gave her. She then asked for a letter of appointment from my company, which they hadn't supplied and I'd never been asked for before. I explained that I was going to Lithuania via Helsinki to join a ship in the Baltic sea. She said because I couldn't produce a letter of appointment she couldn't check me in. I asked to speak to a supervisor. She radiod and a guy came and said exactly what she had said, but also said can't you call your company to send you a letter of appointment online. I told him my company is in Dubai and seeing as it was Friday, nobody would be working. They were adamant I couldn't fly, so I requested a letter with the airports heading, stating the reason they wouldn't let me catch the flight and told him to date it and sign it, so my company could take it up with whoever. That changed their minds, checked me in and I flew to Finland and onto Lithuania. The only time in over eleven years I'd ever had a problem, so considering I use to fly on numerous occasions, one hiccup was no big deal.