By the time you obviously know that another child has chickenpox it's too late to do anything as the contagious stage is 2 days before the spots appear and until all the spots have crusted over.
I had chickenpox twice when I was a kid and I just thought it was a pain in the but because I was itchy, my mum taped mittens to my hands and I chewed through the tops of them
When you have chickenpox your body creates antibodies to fight the infection and thus builds an immunity to the disease so that the chances of getting it again are low (unless you are like me and had a very low immune system). Chickenpox spreads through the air and takes 15 minutes to infect someone, even less time if you have face-to-face contact such as a conversation. It takes 11-20 days before you show any signs.
Personally I'd rather my kids got CP when they were kids because it's not only more horrible as an adult it's also more likely to become complicated.
I'd rather my kids developed a natural immunity, building a stronger immune system (something I never had).