Opening May 9th, it's in the notoriously lousy second major weekend of summer slot that doomed Poseidon, Speed Racer Dating all the way back to 1996. If you recall, Warner Bros. officially started the modern early May summer kick-off with Twister in 1996, opening a full two weeks before Memorial Day (after a very successful trial run in 1992 with WB's Lethal Weapon 3). For at least the last thirteen years, the summer kick-off film usually repeats in the top spot, with only Troy opening number one in 2004 and doing even remotely well in that second-week of summer spot.
Be that slot the second weekend in May or the third, the second-big movie never takes number 01 and usually flops or performs modestly in regards to expectations. Let's just say that I'm pretty sure that Paramount would not be happy with Monster In Law or Horse Whisperer numbers. Push it up to November 21st and it becomes the event of Thanksgiving (it can co-exist with the just moved Bolt) Or it can open in the now-empty November 28th slot. Either way, it becomes the second-biggest film of the holiday season along with Quantum Of Solace. Just my thoughts, with no knowledge of how close the Trek film is to being finished.