That happened in Dane County in 2004. I watched the county by county results on the internet election night. Dane County's numbers didn't change for hours...until Bush was ahead by a few thousand votes...then Dane County finished "counting" and Kerry pulled it out.
Remember the reports that the NO police had disappeared after Katrina and many had gone to Las Vegas? The real story is that they were probably phantom employees who either never existed or were receiving money without having to work. In Jersey City, everyone in my neighborhood used to receive a free turkey on Thanksgiving from the local ward boss. I don't think he paid for it personally.
Which is of course how Dane County was able to ensure the defeat of Republican Scott Klug in the close congressional election of 1990. Oh, wait. He won.
I don't think your theory holds water.