King's Law of Free Stuff on the Internet
Build a free service, and some bastard will come along and abuse it in ways you've never thought of.
"I know ! Let's build a VPN so people can surf the web in privacy !" is almost invariably followed by "Where the hell did all this Netflix traffic come from ?", "Why is our VPN server taking such an interest in all of those military sites ?" and "Why are our proxy caches turning into a mirror of XHamster ?"