Last year I was flying to Brazil with Condor. I don't need a visa, if I stay in Brazil below 90 days (regardless if tourism or business).
The check-in clerk asked me about visa or return ticket. I didn't have return ticket, because at that time I didn't plan my whole trip and have not decided where to go next. I was told, that without a visa or a valid ticket out of Brazil I will not be allowed to check in.
(There was enough time, so I just went and bought cheapest ticket to Montevideo, but that's not important here.)
My question is: did the person have right to deny checking me in? Is this anywhere in regulations or law?