Tram and bus fleet numbers are available in spotters 'reg' books, as are the London Underground, and even more oddly the Glasgow underground trains. I used to work in a shop a long time ago selling such items, and its fair to say many of the customers had 'issues'.
Similar to telegraph pole spotting there are a select few
, and I'm not sure who selected them, who 'do' the post box numbers
Like telegraph poles each post box has a little white number tag 'reg' on it.
In the early 90's in civvy ATC it was not unknown before CFMU and mobile phones, to file a dummy AFTN plan into the unit, from the self same unit, and the plan presented with the originator line stategically torn off. Once the 'duty binker' on the unit had clocked the unusual type/reg flightplan and phoned his mates (landline only) to come and see the movement, the plan was discretely cancelled but the hard copy left on the unit. Cue some very very annoyed binkers
How we laughed
