Spoofing is becoming more prevalent. One reason spoofing is possible is that mobile phones have a setting that allows users to include a Callback# that is different from the sender's mobile device number or mobile device ID. This allows someone to send a text message or call someone while hiding their true number. Carriers are able to capture originating and terminating mobile number information for billing purposes among the mobile carriers themselves. Therefore, they should be able to tell when someone is providing a Callback# that does not match their mobile phone ID. If the Callback# is legitimate, the SMS / text message sender can easily include it in the body of the message. Any other thoughts?