It depends on why/how my children are sick. I can confine my daughter to her room and my son to mine (as I have the tv (w/dvd and vcr) and he doesn't).
We had a bout of strep throat at/after Thanksgiving that I ended up with too. I felt fine other than my throat. I was on antibiotics for 36hrs (because of Tgiving holiday) so didn't close, but left the option for my parents to not bring their children and not charge them. They all came as scheduled. Nobody got sick.
New Years Day I had planned on being open, however I had some bad pizza the night before and ended up with food poisoning. I was able to contact most of my parents and inform them I was sick and taking the day off by the time it hit. I had one dad that I couldn't get a hold of because he was already on his way here. My husband watched that boy (5yrs) and our son play all day. Of course I got teased over this one big time because my parents knew I was going out the night before. I am pregnant (6 almost 7 mos) and sober cab. The guys all drank like fish and me, obviously not a drop of alcohol. Well, they had no hangover, no nothing. I had a bite of undercooked pizza at a bar and end up sicker than sick.
They had the same pizza, but figured they had enough alcohol in their systems to kill whatever germ it was that got to pregnant me.