When Clooney and Roberts check into the motel, Clooney is assigned room #221, and Roberts is assigned room #222. When they go to their rooms, Clooney enters room #222 and Roberts enters room #221. This is confirmed when Roberts boyfriend arrives and knocks on room 221 looking for Roberts as the staff indicated.
Lily is supposed to be starting work as an attorney after she returns from Bali, a trip she departed for immediately after graduating from college. However, in the United States, attorneys (in most circumstances) must attend three years of law school after college and then take the bar exam in the state they intend to practice in; furthermore, the bar exam is only given in July and February. She would most likely be too busy studying for the bar to take an extended trip to Bali.
David and Georgia seem far more upset about the marriage itself than they are about flushing hundreds of thousands of dollars putting Lily through college and law school for a degree she will never use. Response: Georgia switches keys with David saying "I'm going to be listening to you all night, I'm going to do it from a better room."
When Georgia and David are dropping Lily and Wren off at the airport that is presumably in the United States, a sign references "prams" and "trolleys." In an American airport, it should read "strollers" and "carts."
The day before the wedding they go to a remote beach but Georgia (Julia Roberts) initially decides to stay behind to care for Paul. When the party reaches the top of a hill to enjoy the viewpoint, Georgia just catches up. So either she found a chopper (which silently dropped her in the jungle) or someone gave her a ride to this remote part of the island and then she found her way running crazy fast through the jungle.
Julia Roberts' character states she was headbutted. George Clooney's character says "Let me see your nose." Her nose was hit, but she hadn't mentioned that information.