I travel for work and seldom know what my schedule will be. I generally browse the sites a few days ahead of time and might reach out to one or a few masseurs to find out their Outcall rates, availability, and just to see how friendly they are over messaging.
I do end up booking a lot of massages last minute because of my work schedule. Not offended when someone can’t make it work but I also don’t hit up any masseurs that list they need advance notice in their profile if I can’t give advance notice. If you don’t have something along those lines in your advertisement then maybe that would help?