As mentioned by @Arrgh , Rogers MC does charge 2.5% forex, but they also give you extra cashback points.
So in the end you are ahead by 1.5% in rewards.
Though I would be careful with situations like expensive hotel and flight bookings in which you could get large refund / re-billing cycles if there is any change in the booking. You could lose a huge amount due to forex margin, and therefore I use Home Trust VISA in these cases.
What if there were no hypothetical questions?