The only tactical advantage to seeing Indiana Jones and the Kingdom of the Crystal Skull in Cannes on 5.18 is that critics there will have a jump on those seeing it stateside by perhaps as little as seven or eight hours.
The Cannes press screening will happen at 8:30 am with reviews going up an hour or so after it ends at 10:35 am — make that 11:30 am to 12 noon, Cote d’Azur time. That’s 6:30 am to 7 am New York time, and 3:30 am to 4 am L.A. time. If U.S. domestic screenings happen in the evening, the word from Cannes will be exclusive for two-thirds of a day, give or take. Obviously less so if they happen in the afternoon. I’m hearing that U.S. screenings may begin around noon or 1 pm in the east.