If your account is in an overdraft position, or would be put into an overdraft position by processing an Interac Debit contactless transaction including a Transit Open Payments transaction; particularly if you do not have overdraft protection on your account, the associated payment authorization request would typically be denied by the bank. Your account would not go into overdraft or have any associated fees. In that instance, if you have already been provided with access to the transit system and bank did not pay the transit authority, then you will owe the transit authority money. In some rare instances your account may be put into an overdraft position by a Transit Open Payments transaction. This could only happen under the variable fare payment model (described under another Q&A) and depends on whether or not the bank holds funds from the time that a transit authority provides the bank with an estimated cost for your travel, and the time that the final fare is calculated and presented to the bank.