Unless is an obvious shift that looks more like someone moved the camera than a tolerance of the movement, as long as the plates can still be read, most probably don't spend much time looking at the tightly zoomed in plate images as much as they do looking at other cameras.
In my case, my LPR camera one morning displayed out of focus My one LPR cam over the years has "swayed" from the original numbers, meaning that if zoom/focus were 900/1260 initially, over time it is like the components have stretched out from use and I had to change the numbers to 905/1267.