I know at some gas stations if your Credit card or debit card is authorized for lets say 100 dollars and it takes 50 to fill up. Some gas companies take a full 24 hrs to release the remaining money left over.
We do the same to Americans though. It's somewhat understandable considering cross-border preauthorization procedures, but not good for helping tourism.
No, funny though. The processes for credit/debit cards recognize cards as being from CAD or US banks, not sure whether by their numbers or by information on the black stripe.