You aren’t providing the service across the border. The service is in your own country. The buyer is using telecommunications to make an order across the border

You aren’t providing the service across the border. The service is in your own country. The buyer is using telecommunications to make an order across the border. The buyer is the one responsible for knowing their own local laws and should be responsible for managing them. If a Saudi Arabian couple ordered a gay wedding cake from a baker in Montreal, over the phone from Saudi Arabia, in preparation for flying to Canada to get married, which laws apply? To whom?