It has long been a staple of telecom law that telcos could not decide what went through the tube. According to the article below, this principle does not apply to text messages. One academic apologist goes as far as claiming that competition will look after the problem. He misses the point that under present arrangements there is only one way to reach a mobile user with a text message, though his/her operator (an equivalent condition does not exist in the Internet). Until that changes, the common-carrier principle must applied, be it for text or voice.