When using Skype messaging to a mobile number, you can enter your real mobile number as the 'from' address (In Skype settings). To do this Skype first sends you

When using Skype messaging to a mobile number, you can enter your real mobile number as the 'from' address (In Skype settings). To do this Skype first sends you a confirmation message to the number you want to send from. I'm going to assume the confirmation message is Skype being curious, and that the same technology could be used without confirmation. Or is this an agreement with the mobile operators?