Immigration does not care if you have a room. They CAN ask to see your return flight information to verify that you have the means to leave within 90 days. They can also ask if you have enough money to support yourself
If they ask your destination in writing or verbally make some **** up, "i'm with the band".
Room shopping for a deal when you arrive? My friends have had succe$$ walking into the Rayon at the last minute.