Once, after attending an antique car convention in New England, we decided to go home by way of Canada. In those days you could go in and out on the spur of the moment, because the US government had very open borders in those days. (1960s)
Quebec was 'interesting' because neither of us knew any (or much) French and all the signs were in French. Also, their toll booths were different. We were just passing through Quebec (having entered Canada through New Hampshire) trying to get to Niagara Falls by the upper route.
First toll booth, we handed in a Canadian dollar and got some change back. And drove on.
Second toll booth we tossed one quarter into the change bin and drove on. We were aware of flashing lights at the toll booth behind us, but didn't think they had anything to do with us.
At the third booth, there were officers of the law lined up to stop us.
Evidently, the first toll booth had given us FOUR quarters and we had been supposed to toss one of them into the change bin. And so on. Therefore, we owed the turnpike authorities One Quarter.
Very embarrassed, we explained what we had done and they let us go when we had paid the missing quarter.
I miss that old VW bug we drove then. It was packed full of camping equipment and food to sustain us.
Of course we had no problem getting back into the United States at Niagara. Just had to show our Maryland driver's licenses.