We wandered around the streets, encountering plenty of people in T3 hats, but they were blocking off the set and we couldn't see a thing. As we headed off to find out if we could see anything from the other side of the block, we spotted a small crowd between two buildings, and knew we'd found our viewing spot.
We found ourselves next to a black, glass walled building. The scene was being filmed at an old post office across the street, and we discovered that if we pressed our faces up agains the wall of the building, we could see through it to watch the filming. Above is a photo of what we saw - at first it doesn't look like much, but if you zoom in ...

Yes, that's Shia Labeouf in the suit and Josh Duhamel standing next to him. So the boy was beside himself with excitement at this point. I was only there for my son's sake, and really hadn't expected to see any stars. But I've always had a little thing for Josh Duhamel and before I knew it, had lost my detached motherly cool and was jabbering with two girls in their twenties about how cute Josh Duhamel looked.
So we're still watching a little while later, when all of a sudden I spot Shia walking down the sidewalk on our side of the street in his shirtsleeves. And I start squealing like a 15 year old, "He's coming our way! He's going to pass right in front of us!"

So that was our paparazzi experience. I had a very happy boy. And I thought it was pretty cool too.
