Well this is a take on your topic that might be a little different. Yes, I had a client get sick once. I was booked at his hotel and he was in town on business. He had eaten a lot of food and drink with his business firm and upchucked. He was very apologetic and all ended well.
Now for me, it was a little different. I had a local client book me at his home and we were engaged (in June of 2021). Because of the positioning that he wanted, I ended up getting a knot in my hamstring and I was in total pain. I did my best to hide it, but finally had to stop as the pain was too much. The client wasn't happy, patient or understanding. He was in his late 20's. I left his house immediately, but it took several hours to completely recover with my hamstring. Probably one of the worst experiences I ever had with work.