I think I had a temporary case of lunacy. I heard that from someone, and it does apply, but only to cerain types of sod.
Here's the skinny on stadium turf(from someone who does this sort of thing for a living). This might not be exactly what is going on here, but it's probably close. First, they prep the ground. This includes your sand, gravel, and eventually dirt layers. Then they spend a bit of time prepping the dirt by spraying soil nutrients on it.They let that sit for a couple of days to absorb in, then they put down the sod. They will usually water the sod for about 2-3days straight. Then a regular watering schedule will be applied. The nutrients in the soil will help pull the roots down faster, and the watering will help as well. After 4-5 days, the soil should be set. After 2 weeks, its ready for use. 3 weeks and you can play ball without a worry in the world.
As for why they haven't set it up yet, could be that they're still driving trucks across it. Some of the pics being posted still show trucks on the sideslines. Maybe they're waiting for all traffic to get through before they set it down?