Make sure you wouldn't write note anything you wouldn't want the customer reading. I've accidentally taken a note about a customer, but made that note in the text field and sent my customer my notes on the appointment.
I think something with about the text button being DIFFERENT. like instead of just going from grey to green and saying "send" which looks remarkably like "save" especially when you've got another person out on a test drive, and you just want to add some things to the system to remember later.
IDK, like a different color, a quick message that says wanna send that?