I work shifts, and I get a weeks worth on Monday for the week in advance (Friday onwards), so very little notice. Some of my shifts at the moment, there is very little work for me to do, and if I worked 9-5 basically all my appointments would be in work time. I'm not going to go out of my way to make sure appointments are in work time, but how unreasonable would it be to give them the same notice of my appointments as they give me with my shifts? If I worked set shifts I'd let them know as soon as I got any that clashed with my schedule, but right now I don't know which appointments would clash, because I don't have a schedule.
YABU-tell them as soon as you get them through
YANBU-tell them as soon as the rota shows a clash