The van was blocking a narrow road and I wondered whether the “can’t convince them” was directed at traffic wardens determined to put a parking ticket on the van. Maybe the removal company was encouraging its drivers to confuse the traffic wardens if they weren’t convinced by arguments. All very mysterious, and at intervals during the day I would return to the puzzle to try and work out its meaning. And each time I did this I would start to smile, surprised at having encountered something slightly surreal on the side of a very ordinary removal van on a very ordinary street.
Has anybody reading this any suggestions as to what the writer of this message could mean?