If you're in the New Orleans metro, be careful of driving in Gretna with an expired brake tag. They'll auto-run your plate while you're sitting in traffic and zap you for what was a $300 ticket 7-8 years ago.
My plate got auto-run this way back in 2005 in Baton Rouge. No moving violations or anything untoward -- cop was just sitting behind me in traffic and auto-ran my plate. That was my introduction to automatic plate-scanners.