First let me inform you a massage while you are sick will just make you sicker. Massage moves fluid and soft tissue that will take your sickness in one part of your body into almost EVERY part of your body. So while sick if you think a massage will make you feel better you are WRONG!!!!!
Second reason, have some common courtesy. Your poor massage therapist did not sign up to be stuck in a room with a sick person for an hour just so that they could get sick and can't work for a week and lose out on pay because you have no manners.
Just picture yourself being on an airplane with a sick person sitting right next to you, coughing and sneezing all over you and you can't do anything but sit there and take it. Not fun! So don't take your germs to your therapist. They would rather you cancel and reschedule than touch your snotty, coughing, fever sweat covered body.
Heart Ya, Ginger