As usual - cell carriers try to bill at both ends.
If the customer is already paying for incoming text messages (and paying a lot, mind you) - there is absolutely no reason to bill anyone else for it.
What would make sense would be to bill the sender - but not the receiver - but billing both ends is double dipping and pure greed. Especially when we're talking about a text message which costs probably a fraction of a fraction of a cent to deliver.
