"Your baseball analogy is inappropriate since the baseball is being used inappropriately or was used in a way that an accident happened. So, yes, the adult is still liable."
I stated in my post that it was an accident. Surely no one here expects a young child to be able to throw a ball perfectly and on course 100% of the time? Not even professionals can do that. So I, as a parent, am acknowledging that there is a risk my son (or any child) could hit a car or a window if I let him play with a baseball, and I am responsible for any damage he causes.
Two years ago, a 20 year old college student was throwing a football with his friends and hit my car mirror and broke it off. He left a note with his number and paid for it to be repaired. I am not sure what you mean by "being used inappropriately". Unless you expect zero accidents from a child throwing or hitting a baseball your reply makes no sense. How else is he supposed to play with a baseball? just hold it in his hand and carry it around?
"So, then, getting just one MMR shot is "doing everything you can to try and prevent your child from getting an infectious disease?"
I would say your child has to be up to date on their vaccines. So if you have a one year old, then yes, having just one MMR shot is doing everything you reasonably can to protect your child from contracting and spreading measles.
"I would say that having a vax be your way of "doing everything you can to try and prevent your child from getting an infectious disease" is quite the easy way out. Working day in & day out to support your child's immune system & to make it truly healthy, that's "doing everything you can to try and prevent your child from getting an infectious disease."
As I said before, none of that has been proven to reduce the spread of diseases like Measles and chicken pox in any measurable way, since nearly everybody still got those diseases until the vaccine came around. So vaccinating is the best thing you can do to prevent your child from contracting measles and many other infectious diseases.
"And who would get to determine the medical exemptions?"
Medical doctors would.
"And, how severe were these illnesses most of the time? Not bad, right? Yes, some got very sick & some died. I'd take a mild case of chicken pox in my children any day over shingles in their teens or adulthood. Any day. And, to be brutally honest, I'd rather my child have a life long issue w/ an illness than a life long issue w/ a vax."
A lot more died from the diseases than from the vaccines that prevent them. There is no way to predict if your child is going to be the one that dies from measles, or becomes deaf from measles, or develops SSPE from measles. So maybe you would take a "mild case of chicken pox" over shingles but you can't know ahead of time if your child is going to have a mild case or not. Plus, the vaccine most likely will protect your child from getting shingles. Having chicken pox naturally is what causes shingles in adults.