I've never been to NOLA, but started watching some streaming camera footage from Bourbon Street on EarthCam, as some friends of mine had visited and enjoyed it.
I'm in the Pacific time zone, so I could watch late-night or early morning footage easily.
I was very impressed by the daily cleanup on Bourbon Street. Several garbage trucks would come by in the early mornings, around 4-5 am picking up the trash put out by restaurants, bars, and stores and empty the sidewalk trash bins. They also picked up stray boxes or stuff on the sidewalks. Then the street cleaners would come out and thoroughly wash the street so that very little, if any, debris or garbage was there.
On NYE, there would have been a lot of trash bags and stuff and still a lot of people at ~3:30 am, before the cleanup people came by about 4 -5 am. Certainly, if there were IED left streetside planted by others, they knew to commit their acts before that time.