Here in Vermont, license plates, issued sequentially in the ABC-123 format, cannot start with letters I or O, which makes sense, but J is also forbidden, I guess because it's also too similar to a zero. The plates go right from HZZ to KAA. We'll have to wait a few years to see what happens with Q, as this tiny state has yet to even get all the way through the KAA-KZZ series.
In serialization schemes, yes, glyphs are often avoided that can be mistaken for others (OCR/ALPRS resolution limits, specks of contamination, and screening like smoke/fog/smudged flatbed scanner glass). This mainly means 1 = I and Q = O = 0. But some fonts render V with the top 2/3s of their vertical elements straight (recall the 80x25 text mode version of V, and old fixed-font printers). I doubt they would have ever feared J being mistaken for O or 1, but J = U is possible with extreme point perspective foreshortening or large contamination specks like those one might see on plates due to road splatter (although in that event, one would think letters like F would also be verboten to prevent misrecognitions as letters like E).
20th Century Fox Television has a serial numbering scheme for every television series and episode it produces. The format is ScccNN (S = season number as 1-9 plus A-Z for 10 and up), ccc = unique show ID (e.g. ABF = The Simpsons, ABX = The X-Files, ACX = Family Guy, ASA = Bob's Burgers, AYW = The X-Files reboot, ATS = American Horror Story, etc.), and NN = episode number (01-99). People started noticing that all of Fox's long-lived shows were skipping I, O, Q and U for the season prefix. When the completely unexpected ended up happening to the creators of this numbering scheme (The Simpsons lasting all the way to and beyond Z), they gave up on OCR compatibility and proceeded to use U, then Q, then O, etc. for the seasons following Z. Apparently by then, they figured that the days of real paper records were so officially over, OCR considerations were no longer necessary. (Just this year, the studio had to enhance this universal production numbering format to simply give up on letters. Simpsons episodes airing during the 2024-2025 period -- its 35th season -- will now be numbered simply 35ABF##, it seems.)
Fascinating information about the origins of the A and N callsign prefixes, by the way (Army and Navy). I had never understood why those were chosen. W also makes sense for west coast (at least during the military days). But I am curious why they chose K for the east during that same period. Does anyone happen to have the answer to that one last part of the riddle?