Some Canadian restaurants (especially in tourist areas) will accept U.S. currency at a more favorable exchange rate

Question:

Some Canadian restaurants (especially in tourist areas) will accept U.S. currency at a more favorable than the banks will give. Why?

Exchange Rate
The value of one currency for the purpose of conversion to another. Exchange Rate means on any day, for purposes of determining the Dollar Equivalent of any currency other than Dollars, the rate at which such currency may be exchanged into Dollars...