Couple things to consider. First, this was written up in 2003, and expanded on in 2004. I don't know if text messaging is as big then as it is now. Secondly, we weren't sending them a text message. While asking them might not hurt, we didn't want a cell phone. Asking for a phone number "just as for SMS messaging" might be more confusing. I'd rather just ask for the phone number, and fix it myself.

At least, that were my thoughts at the time.