"You mean people don't play baseball on Xxxxx, xxxx?"
The use of 'on' indicates that Xxxxx is an island or another world.
"And—" she waved at the heavily laden tables dotted across the grass "—since I see the caterers are waiting, I'll keep it short, as well."
This indicates to me that 'she' and xxx share so many common concepts that another world is unlikely, so Xxxxx is an island, but xxx's inability to identify a baseball bat means it's an isolated island. The reference to sin could indicate an obscure sect that has withdrawn from society.
Now I'm stumped again. Can anyone else take it from here?