The people doing random things with fake .dev domains were going to get bit in the ass one way or another. You can't just make up your own domain and hope no one ever does anything conflicting with it.
Actually you can! You just need to use one reserved for that purpose:
> In 1999, the Internet Engineering Task Force reserved the DNS labels example, invalid, localhost, and test so that they may not be installed into the root zone of the Domain Name System.