Not the most expensive, but I dr'd (mcm) a box of gemstones to a goldsmith on my route. The guy was semi-retired and worked out of his house.
Next morning, my on-car pulled me aside and asked me about the delivery. Turns out, it was about 15-16k worth of diamonds and emeralds. The barcode was an 03, no signature required. Somebody in LP wanted my head on a platter for dr'ing it. He said it came through as a high-value, but the 22.3 that handled high-values in our building double checked his records and said it didn't.
I went back, got a signature (I knew the guy for over 30 years and had bought a lot of jewelry from him over the years) and all was good.
The next morning, the high-value guy pulled me aside, and told me that somehow magically that package had been back-dated as a high value.
Go figure.