I got a similar message but no explanation. Perhaps it goes against protocol? I call to confirm an appointment if the signer doesn't answer and doesn't have voice mail, I ask for an alternate phone number. If no one answers that one either, I email. I only text that I am calling to confirm an appointment for such time and date. I do not like to get into details during a text due to the privacy issue. I have been prompted by some loan companies to text if no answer to a voice message. If I read in the instructions, not to text I would respect that.
Perhaps some VIP customers are getting annoyed with notaries who are trying to open up discussions beyond confirming appointments. We can all guess and come up with different scenarios, so it is best not to text. Texting, for me is not my go-to. Even with no confirmation, I have to print and show up for the meeting. So far every one of my silent signers has been there expecting me. Some people are just really uncomfortable with technology but they still need their documents signed.