It was Reno's life, Tidus wasn't his guardian. He doesn't know Reno well enough to guess the smile a fake; and it's been a long day, usually is on the last. So who's he to judge Reno for how he looks or doesn't when he doesn't look that great either?

"Sure. Drinks are probably cheaper here than on the train." Not that Tidus knew--he only just about remembered you could buy alcohol on the train. But he's looking beyond the counter, not at Reno, clearly waiting for a turn to ask to make an order, once the person behind it was done with another customer.

"No giant monster showed up that you all had to fight?"