And that airline was breaking the law. It does not matter whether or not they charge for seat selection. The law states that if the passenger has paid for a berth and wishes to use a certified carseat in that berth for a child who fits in the carseat per mfr. recommendations, then the parent gets a pair of seats to accomodate the regulations re: emergency egress.
Sorry, should have mentioned it was a Canadian airline, so the US laws do not apply.
I understand why it is a rule, but it does piss me off that people can abuse it to get the airline to force other eople to move.