My sister, mom, and I are all cursed with stomach problems. At least one of us is sidelined on each trip for a couple hours at least one day. We are so used to it, no one cares at all when we leave each other.
I do feel slightly guilty; however, because my sister was not feeling well during our trip to DL for New Year's Eve, and while she was sick and resting at the Grand Californian, I stumbled across a sneak peek of Mike and Sulley. I didn't know for sure it would be open the whole day, so I rode it without her.
Riding a new attraction for the first time without your family/BF, whoever, is pretty cruel. Don't do it. I still feel pangs of guilt talking about it.
Oh, and it was still open when she came and we went on it together. And yes, I admitted my wrongdoing to her. She said it was fine, but still...it was pretty mean of me.