The forum thread where this is discussed:
- http://bitcointalk.org/index.php?topic=40264.msg1000405#msg1...
The URL that is sent is a bearer code (spendable by anyone with access to the data). I question whether this approach, and consider another problem due to SMS being a channel controlled by the government here:
- http://bitcointalk.org/index.php?topic=90901.0