Shameless plug: The guys behind OpenTTD are also working on a remake of RCT called FreeRCT [1]. It's still in its infancy and it doesn't have many features, so any contributions are welcomed!
If your child is vaccinated, they aren't really at significant risk of catching a preventable infection from an unvaccinated child, since that's the sort of thing vaccines are designed to prevent. This isn't to say that anti-vax is a rational position, but I don't think (disclaimer, I'm not a medical professional) it puts vaccinated children at additional risk.
Craigslist has a really bad history of abusing its users. For instance, a few years back they changed the TOS so that CL becomes the copyright holder of all ads placed on the site.
There's probably a provision in the TOS that says that you implicitly agree to the terms by virtue of using the service. I don't know for sure, just speculating.