Add "the booking is / is not non-refundable" custom code condition

I want to create a custom code to automatically remind all guests who book with the non-refundable option that we will be unable to refund their booking fees should they cancel and that they should purchase travel insurance. I will also give them the option of cancelling for a full refund within a day or so of booking.

Most of my guests use the non-refundable option in order to save money; however, when they cancel, they still ask for a refund putting me in a tough position. I want to be upfront as soon as they book so they know what they are getting into.