Yes, when taking GO Transit, make sure to use the same method of payment to tap on and off for a trip. If you use a Visa card to tap on, you cannot tap off with a mobile wallet, even if your mobile wallet is connected to the same card you used to tap on. If you do use a different payment method to tap off, it will be recognized as the start of a new trip.
If you tap off with a different card than the one you use to tap on, the PRESTO device will read that as you tapping on again with a different card and you will be charged another fare.
If you tap the wrong card for a fare inspection, you may receive a fine for not paying your fare. When approached by a fare inspector, make sure to tap the payment method you used when you first boarded.
If you forget to tap off, at the end of the day your card will be charged a fare for the longest trip on the transit system you used. To avoid paying a higher fare, make sure you always tap off at the end of your trip with the same contactless payment method you used to tap on with.