Well try doing a search for "WOW private server". People legitimately crack the packets in network traffic off of their own backs, to make server emulators! So even these games are at risk! Serious risk.
Indeed, I have played extensively with an EQ emulated server, and played on a WoW one. The problem is the content is never as good and connections are more laggy, as a player on a pirate server you are getting a far lesser experience than the main game. WoW also doesnt help matter by segregating the community into different realms, which defeats the purpose of playing online and means pirate server communities can thrive with similar environments. I've never agreed with this aspect of the EQ/WoW model. I don't see the point in realms, except as a shortcut to poor game design.