Locally I see it most of the time. If you are a two parent family, you can get a family ticket, with 10% to 20% knocked off the price. As a lone parent, you get to pay full price.
Or with camping, they charge as a basic price - 1 tent, 1 car, 2 occupants (adults). I then have to pay an adult price for one child as the 2nd occupant, then a child price for my other child. Its not like we are a single occupant where you are charged extra, its a case of 1 adult, 2 children, 2 dogs.
It often feels discriminatory but I'm guessing there are sound business reason's why we often have to pay more? Please say their is because it gets my goat! Let alone when you do get a 1 adult offer, its for 1 adult and 3 children...like all single parents have 3 children?!