And the updates aren't just the files patched on to your game folder, most is on the server. They would probably have to make a test server... Sounds fun. =D
Yeah, test servers are probably the best option. Outspark can test all they want at their offices but they only have certain types of computers and operating systems to work with.
It's much like how when I use a certain font to build a website to make it look nice but people who do not have that font will see ugliness on their computer.