I worked with the Tech crew in my high school theater department for a couple of years. There we explicitly removed network connectivity from from the sound/lighting computer to increase stability.
This is fairly standard. As mentioned down thread, an "air gap" is a huge safety measure for production computers. Lowers the likelihood of a virus infecting the machine, and if a botnet does get on there somehow, it still can't talk to C&C. You can't just have anti-virus running on your Watchout display machines or your SFX playback machine, that CPU load is awful. So we disconnect!
