Personally, I would avoid that method. Most virus scanners will block access to this host file remotely. You could potentially do the same thing with your Balance routers DNS service. Basically, you are wanting “something” that translates google.com to forcesafesearch.google.com. I don’t know of a clever way to do that, but if you are already going to set static IP lookup information in the host files across your windows network – you can set up “Local DNS Records” in the Balance LAN settings to do this in a centrally managed way.
I am sure that someone around here will have a crafty mechanism to do this with strictly DNS trickery. Seems like you could create a local alias/cname for google.com to map to safesearch.google.com (or something like that). Kind of nice of google to offer a network based solution to an application level parameter by offering VIPs specific to safesearch – I wasn’t aware that they were doing that.
Good luck in your adventures.